—What are you doing?
—I am _________ a letter.[ ]
A. write
B. writing
C. writes
答案:B
XHP7型牙轮钻头的结构特征是()。
A、自洗移轴式布置;
B、自洗不移轴式布置;
C、非自洗式布置;
D、移轴非自洗式布置。
They________the trucks with boxes of food and sent the goods to the disaster areas in Sichuan province.[ ]
A. supplied
B. provided
C. loaded
D. unloaded