27；21；20；15；12；18；35；12；12；24；8；18
通过思维，能从已知推断出未知来，这说明思维具有（）的特点。
A.直观性
B.形象性
C.间接性
D.概括性
271. Wait for me for a few more minutes. I am _____ to a letter from one of my former classmates at college and will finish writing very soon.
A．replying
B．answering to
C．replying to
D．answering for
