I recently watched a short news report about a study in a chinese university where they tried to find out whether men are more vain than women. The researchers made appointments with their subjects to be interviewed and each has to wait in a waiting room before being interviewed. In each room there is a one way mirror where researchers can video tape the subject's action without being seen. In that study, men looked at themselves in the mirror more than the women.
1) past perfect
2) past simple
3) past continious
4) future simple