The man we followed suddenly stopped and looked as if ________ whether he was going in the right direction.
| A．seeing | B．having seen |
| C．to see | D．to have seen |
The owner of the house moved to west Beijing last month, which is ________ he decides to sell this house.
| A．why | B．when |
| C．where | D．how |
A draft regulation on school bus safety management was made public by the State Council, with the public________to give comments.
| A．to invite | B．inviting |
| C．invited | D．having invited |
Natural learning environments inspire a burning ________ to learn, the key to a productive lifestyle.
| A．position | B．desire |
| C．impression | D．opinion |
—Jack's car hit a big tree yesterday.
— ________？ In my memory, he is always a careful driver.
| A．How come | B．Guess what |
| C．So what | D．Why not |
Europeans always hold their fork in the left hand, ________Americans switch it between their left and right hands.
| A．before | B．because |
| C．while | D．since |