______ his son away to college, the old couple got more room in the house.
A:As
B:For
C:Through
D:With
热带和温带的分界线是( )
⑴____ A. smile B. small C. sport
⑵____ A. sleep B. slim C. slow
⑶____ A. swim B. sweet C. swan
⑷____ A. fresh B. train C. great
12k+7k-10k+5=____