It was never clear ________ the man hadn't reported the accident sooner.(2011·江苏)
As a simple and convenient way to get ______ latest fashions online, online shopping also has ______ major problem — you can’t see whether they fit or not.
—— Will you do me a favor and pick me up tonight?—— __________.
It is on September 1st students go back to school every year.
The boy was excited he went to Beijing.
In fact, there is _____ thing as a free lunch in the world.