Answer: C

Explanation:

‘Ran’ should be replaced with ‘run’, as ‘to’ is followed by the first form of a verb, e.g., it is difficult for anyone to run on a slippery surface.

Answer: D

Explanation:

‘Their’ should be replaced with ‘his’, as we are talking about one person, either Tom or Peter.

Answer: C

Explanation:

‘Until’ should be replaced with ‘by’: Can you repair my car by Friday?

Answer: C

Explanation:

• We use ‘will have’ when we are looking back from the present (a point in time) when something will have happened, e.g., by the end of this year, the scientists will have discovered a vaccine for swine flu.
• I will phone at five o’clock. He will have got home by then. ‘Would have’ is used as the past tense form of will have, e.g., I phoned at five o’ clock. I knew she would have got home by then.

We also use ‘would have’ in past conditionals to talk about something that did not happen, e.g., if it had been a summer season we would have gone for swimming. So ‘will’ should be replaced with ‘would’: If Tom had known it yesterday he would have helped him.

Answer: D

Explanation:

The definite article ‘the’ is used before the names of seas, rivers, lakes, etc., and before the names of mountain groups. So, add the article ‘the’ before ‘Himalayas’ and ‘Ganges’.