1．As we all know, China has the ________ population in the world.
A．smallest
B．most
C．biggest
2．I’m sorry you missed the bus. It ________five minutes ago.
A．left
B．will leave
C．was leaving
D．is leaving
3．—Have you done your homework yet?
—Yes. I ________ it last night.
A．do
B．did
C．will do
D．have done
4．—Did you buy ________?—Yes, I bought something for my father.
A．nothing special
B．something special
C．anything special
考查复合不定代词辨析。nothing special没什么特别的；something special一些特别的东西，something用在肯定句中；anything special一些特别的东西，anything用在否定或疑问句中。根据“I bought something for my father”可知，此处指买一些特别的东西了吗，排除A，句子是疑问句，所以用anything，排除B，故选C。
5．He ________ me his name, but I can’t remember it now.
A．tells
B．is telling
C．told
D．will tell
考查动词的时态。根据“but I can’t remember it now”可知，“他”过去某时告诉过“我”名字，应用一般过去时，谓语动词应用过去式。故选C。