Choose the correct variant:

1) Though I was sitting in the last row, I could (see / seeing) the film well.
2) I (have met / met) this man before.
3) He couldn't find his watch. He (has / had) lost it.
4) I have been (waiting / waited) for you for 20 minutes already.
5) Many tourists have (visited / visiting) that castle.
6) The performance (is starting / starts) at 7 p.m.
7) I (won't tell / am not telling) anyone your secret.