---Tell us, Mark, what is the cause of the American Civil War?
---Well, is it _______the black slaves wanted freedom?
| A．how | B．why |
| C．because | D．when |
—What’s the weather like tomorrow，John?
—Well，I______it，for the scenic pictures drew my attention as the weather forecast was going on.
| A．was missing | B．missed |
| C．will miss | D．had missed |
Proper first aid can save a seriously injured person，especially when he or she is bleeding heavily or______.
| A．has poisoned | B．was poisoned |
| C．has been poisoned | D．is poisoning |
—I took a picture of you just now.—Really? I______with attention.
| A．didn’t look | B．wasn’t looking |
| C．am not looking | D．haven’t looked |
—I remember I ______my bag somewhere around here.—Really? I never saw it.
| A．left | B．leave | C．was leaving | D．had left |
The man often feels lonely.He seems to have______ most of his friends.
| A．fallen | B．dropped |
| C．stopped | D．made |