【单选题】________ the difficult things happened when I can't adjust myself? [ ]
【单选题】听力原文:What is putting things together that seem to belong together? (15)
【单选题】What does the sentence 'The air helps purify the water' illustrate?
A.
The ecological balance.
C.
The earth's limited resources.
【单选题】I didn't know what ____ to her last night. [ ]
【单选题】-----What _____? -----I______my key and can't open the door.
D.
has happened, have lost