Must have V3 vs. Should have V3 (Perfect Modals) – English Grammar Exercises for B2
You are reading a live news report updating the public on a high-profile art theft at the National Museum. The journalist is reporting the police’s deductions and criticizing the museum’s security failures. Choose the most appropriate option (A, B, C, or D) to complete each sentence.
1 There are no signs of forced entry on any of the doors or windows. The thieves ______ a master key to enter the building.
(A) must use
(B) must have used
(C) should have used
(D) must had used
2 The museum’s alarm system was completely offline during the heist. The head of security ______ the system before leaving for the night.
(A) should of activated
(B) should activate
(C) must have activated
(D) should have activated
3 The stolen sculpture weighs over 200 kilograms. The perpetrator ______ several accomplices to carry it to the getaway vehicle.
(A) must to have had
(B) must have had
(C) should have had
(D) must have
4 We received multiple warnings from Interpol about a potential heist last week. The museum board ______ security measures immediately.
(A) should have increased
(B) must have increased
(C) should increase
(D) should to have increased
5 The police discovered the guards’ coffee was laced with sleeping pills. Someone ______ into the break room before the shift started.
(A) must sneaked
(B) should have sneaked
(C) must have sneaked
(D) must of sneaked
6 The priceless painting was cut cleanly from its frame with extreme precision. The main suspect ______ a professional art thief.
(A) must have been
(B) should have been
(C) must be
(D) must had been
7 The primary suspect claims he was at home, but his fingerprint was just found on the glass display. He ______ at the scene of the crime!
(A) must be
(B) must to have been
(C) must have been
(D) should have been
8 The museum director is facing severe criticism from the public. He ______ the city’s funding to upgrade the surveillance cameras years ago.
(A) should have used
(B) must have used
(C) should of used
(D) should use
9 A suspicious white van was seen speeding away at 3:00 AM. The stolen artwork ______ in the back of that vehicle.
(A) should have been
(B) must been
(C) must had been
(D) must have been
10 The night shift guards did not patrol the East Wing at all. They ______ their standard rounds as strictly required by protocol.
(A) must have completed
(B) should have completed
(C) should complete
(D) should had completed
11 The laser grid was bypassed using an incredibly complex series of mirrors. The criminals ______ a lot of time planning this exact route.
(A) should have spent
(B) must spend
(C) must have spent
(D) must have spend
12 It took the local police nearly an hour to arrive at the museum. The emergency dispatcher ______ the anonymous tip more seriously.
(A) should take
(B) should of taken
(C) must have taken
(D) should have taken
13 The museum lost its prestigious art insurance policy because of this incident. The management ______ the mandatory safety guidelines.
(A) should have followed
(B) must have followed
(C) shouldn’t have followed
(D) should had followed
14 The CCTV footage from the server room was permanently deleted. The hacker ______ remote access to the internal network.
(A) must gained
(B) must to have gained
(C) should have gained
(D) must have gained
15 The frame was left behind, perfectly unscrewed with specialized tools. It ______ by someone with extensive knowledge of museum hardware.
(A) must have been removed
(B) should have been removed
(C) must be removed
(D) must have removed
16 Unbelievably, the stolen masterpiece, “The Golden Dawn,” was completely uninsured! The board of directors ______ it for at least ten million dollars.
(A) must have insured
(B) should insure
(C) should have insured
(D) should have been insured
17 Detectives found a piece of torn fabric near the air vent. The thief ______ his jacket on the sharp metal edge while escaping.
(A) must have snagged
(B) should have snagged
(C) must snag
(D) must had snagged
18 The chief of police stated that the control room was left completely unattended. The security guards ______ their posts to play cards!
(A) mustn’t have left
(B) shouldn’t leave
(C) shouldn’t had left
(D) shouldn’t have left
19 Only a highly agile and flexible person could dodge the dense grid of infrared beams. The perpetrator ______ a gymnast or a professional acrobat.
(A) should have been
(B) must be
(C) must have been
(D) must to have been
20 The international borders are closed, but the investigation is stalled. Detectives now believe the priceless artifact ______ the country hours before the alarm even rang.
(A) must have left
(B) should have left
(C) must of left
(D) must left
ANSWER KEY & EXPLANATIONS
1 (B) must have used
- Why it’s correct: Asserts a logical deduction based on physical evidence (no signs of forced entry -> they certainly used a master key).
- Error Analysis: (C) should have used is a Meaning Trap (it advises the thief that using a key was a good idea). (A) is the wrong tense (present). (D) is a structural error (must had does not exist).
2 (D) should have activated
- Why it’s correct: Criticizes an obligation that was neglected in the past (the head of security was supposed to turn it on, but didn’t).
- Error Analysis: (C) must have activated is a Meaning Trap (deducing that he “certainly turned it on” contradicts the fact that the system was offline). (B) is the wrong tense (present/future). (A) is a common spelling/phonetic error (should of).
3 (B) must have had
- Why it’s correct: A logical deduction based on physical evidence (the sculpture weighs 200kg -> they certainly had accomplices).
- Error Analysis: (C) is a Meaning Trap (implies they should have had accomplices, as if giving advice). (D) is the wrong tense (present). (A) is a structural error (adding “to” after must).
4 (A) should have increased
- Why it’s correct: Expresses regret and criticism because the board ignored the warnings and failed to increase security.
- Error Analysis: (B) is a Meaning Trap (deducing they “did increase” security contradicts the fact that they were robbed). (C) is the wrong tense. (D) is a structural error.
5 (C) must have sneaked
- Why it’s correct: The police’s logical deduction of how the thief drugged the coffee.
- Error Analysis: (B) is a Meaning Trap. (A) is a structural error (missing ‘have’). (D) is a common phonetic spelling mistake (must of).
6 (A) must have been
- Why it’s correct: Draws a conclusion about the suspect’s identity based on the professionalism of the crime scene.
- Error Analysis: (B) is a Meaning Trap. (C) is the wrong tense (present deduction). (D) is a structural error.
7 (C) must have been
- Why it’s correct: A solid deduction based on hard evidence (a fingerprint).
- Error Analysis: (D) is a Meaning Trap. (A) is the wrong tense. (B) is a structural error.
8 (A) should have used
- Why it’s correct: Public criticism directed at the director for failing to use the budget for security in the past.
- Error Analysis: (B) is a Meaning Trap. (C) is a phonetic spelling error (should of). (D) is the wrong tense.
9 (D) must have been
- Why it’s correct: The police’s working hypothesis/deduction about the white van.
- Error Analysis: (A) is a Meaning Trap. (B) is a structural error (missing ‘have’). (C) is a structural error (must had).
10 (B) should have completed
- Why it’s correct: Criticizing the guards for failing to fulfill their mandatory duties (they were supposed to patrol).
- Error Analysis: (A) is a Meaning Trap (deducing they “did complete” the rounds contradicts the previous sentence). (C) is the wrong tense. (D) is a structural error.
11 (C) must have spent
- Why it’s correct: Deduction based on the complexity of the crime scene (the mirror system).
- Error Analysis: (A) is a Meaning Trap. (B) is the wrong tense. (D) uses the wrong verb form (needs the past participle ‘spent’, not ‘spend’).
12 (D) should have taken
- Why it’s correct: Criticizing the emergency dispatcher for their poor performance and slow reaction.
- Error Analysis: (C) is a Meaning Trap. (A) is the wrong tense. (B) is a phonetic spelling error (should of).
13 (A) should have followed
- Why it’s correct: Criticizing management for violating insurance protocols.
- Error Analysis: (C) shouldn’t have followed is a Meaning Trap (it means “it was a bad idea to follow the rules,” which is illogical). (B) is a Meaning Trap (deduction). (D) is a structural error.
14 (D) must have gained
- Why it’s correct: A cybersecurity expert’s deduction: the deleted data proves the hacker definitively gained access.
- Error Analysis: (C) is a Meaning Trap. (A) is missing ‘have’. (B) has an unnecessary ‘to’.
15 (A) must have been removed
- Why it’s correct: Passive perfect modal used to deduce what happened to an object (the frame was certainly removed by a professional).
- Error Analysis: (B) is a Meaning Trap. (C) is the wrong tense (present passive). (D) is an active voice structure (implying the frame itself removed something).
16 (C) should have insured
- Why it’s correct: Heavy criticism of the board’s gross negligence (they failed to buy insurance for the painting).
- Error Analysis: (D) should have been insured is a structural trap (the subject is “The board of directors,” so the sentence must be active, not passive). (A) is a Meaning Trap. (B) is the wrong tense.
17 (A) must have snagged
- Why it’s correct: Police reconstructing the crime scene through physical evidence (the torn fabric).
- Error Analysis: (B) is a Meaning Trap (advising the thief that they should have snagged their jacket). (C) is the wrong tense. (D) is a structural error.
18 (D) shouldn’t have left
- Why it’s correct: An accusation and criticism of a severe violation (they were not allowed to leave their posts).
- Error Analysis: (A) mustn’t have left is a Meaning Trap (“I deduce they did NOT leave,” which contradicts the evidence). (B) is the wrong tense. (C) is a structural error.
19 (C) must have been
- Why it’s correct: Creating a criminal profile based on the physical requirements of the crime scene.
- Error Analysis: (A) is a Meaning Trap. (B) is the wrong tense. (D) is a structural error.
20 (A) must have left
- Why it’s correct: The final sensational deduction reported by the press regarding the artifact’s whereabouts.
- Error Analysis: (B) is a Meaning Trap. (C) is a phonetic spelling error. (D) is missing ‘have’.
GRAMMAR POINTS TO REMEMBER
- Must have + Past Participle (Crime Scene Deduction): This is the ultimate grammatical tool for investigators and journalists. When you observe physical evidence (fingerprints, cut frames, deleted footage), you use this to state a highly certain, logical conclusion about a past event.
- Example: The camera footage was deleted -> The hacker must have gained access.
- Should have + Past Participle (Accusations of Negligence): Used to point the finger of public criticism at security flaws. You use this to highlight a standard, protocol, or duty that a person or organization was supposed to fulfill in the past, but failed to do.
- Example: The door was left unlocked -> The guard should have checked it.
- Shouldn’t have + Past Participle (Condemning Violations): Used to harshly criticize a severe mistake or rule violation that occurred in the past.
- Example: The guards shouldn’t have left their posts to play cards.
- Passive Perfect Modals (must have been + Past Participle): In true-crime reporting, the focus is frequently on the “victim” or the “evidence” rather than the unidentified criminal. Therefore, passive deductions about past events are incredibly common.
- Example: The frame must have been removed by a professional.