NDA (II) 2017 General Ability Test · Question 46 of 150

Correct — A, have passed. A clause beginning with 'since' and holding a simple past verb — 'since I saw her last' — is answered by the present perfect in the main clause, so the sentence reads 'Years have passed since I saw her last.'

• (b)had passed — The past perfect needs a later point in the past to look back from, and this sentence is anchored to the present moment.
• (c)had been passing — It carries the same fault as 'had passed' and adds a continuous form, which does not suit a measured quantity such as 'years'.
• (d)have been passing — The perfect continuous stresses an activity still going on, whereas counting the years that have gone by calls for the plain present perfect.

The 'since' pattern pairs a simple past inside the since-clause with a present perfect in the main clause.

The clue is the tense inside the since-clause. 'I saw her last' is simple past and fixes a point in the past; from that point the main clause has to run up to the present, and the present perfect is the form that does it.

• 'Since' marks a point in time, while 'for' marks a length of time.
• The present perfect links a past event to the present moment.
• With a counted quantity such as years, weeks or days, the plain perfect is preferred over the perfect continuous.

• Reaching for the past perfect simply because the sentence mentions something that happened earlier.

Asked as a blank-filling item testing the tense a 'since' clause requires in the main clause.

• practice — not a real PYQ

  Choose the phrase that best fills the blank — Two hours ____ since the train left the platform.

  • (a)had passed
  • (b)have passed
  • (c)are passing
  • (d)were passing

  Answer(b) have passed — the 'since' clause is in the simple past, so the main clause takes the present perfect.

• practice — not a real PYQ

  Choose the phrase that best fills the blank — I ____ him since we were at school together.

  • (a)know
  • (b)knew
  • (c)have known
  • (d)had known

  Answer(c) have known — the acquaintance began in the past and continues now.