Jack has been skating four hours ago .A since B. about C.for about D. in
He is so poor that he has no house _____.
The stones are so heavy. How _____ they _____ to the top of the building without modern machines?
No free plastic bag in the supermarket helps to _____ white pollution.
The young man broke his arm in the accident and had to _____ his job.
We _____ walk in the park after supper, talking about all _____ we were interested in.