This question came in the Dhaka university admission exam 2016-17

Q) These differences between the two photographs_______with the help of computer programs

(a) should removed

(b) must be removed

(c) have to removed

(d) could have been removed

(a) and (c) are agrammatical. The question bank says the answer is (d). I think that both (b) and (d) are acceptable answers. Am I right?

  • 2
    Choices (b) and (d) are grammatical; however if the section of the paper is clearly headed or designated as related to the perfect progressive, then only (d) is correct. May 19 at 6:43
  • Two things, “these” implies that there are other differences that should be excluded from this statement, and (b) is somewhat awkward IMO because of the must and computer programs (what if you only use one program, does that mean it was done incorrectly?)
    – jmoreno
    May 20 at 0:20

1 Answer 1


Yes, (b) is perfectly acceptable. Here's a similar passage from the Code of Federal Regulations:

The valve cap, or the reducer when a large outlet is to be used, must be removed with a suitable wrench after the set screws are loosened.

(d) is fine, too. I don't think there's more context to decide which one fits better, right?

Otherwise, I guess that like one of your previous questions, this is another example of a questionable exam question from that source.

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