Question

Put the verb into the most suitable form:
John and I went for a walk. I had difficulty keeping up with him because he ______ (walk) so fast.

• A. walked
  
• B. has walked
  
• C. was walking
• D. has been walking
  

Answer 1

The correct option is C was walking

Option C is the correct answer because the statement is made in the past tense, so it is correct to say that John was walking fast, so he couldn’t keep up.

Option D is incorrect because ‘has been’ is used as a continuation of the past tense in the present, but that is incorrect because the statement is made purely about the past.

Option A and B are incorrect because ‘walked’ means that John had already finished walking, which is incorrect because the speaker was still trying to keep up, which means they were both still walking.