预防疟疾可选用（）
A.氯喹
B.甲氟喹
C.乙胺嘧啶
D.多西环素
E.伯氨喹
参考答案：A, B, D, E
When Tim returned home ten years later, we found he changed so much that we could hardly _____ him. [ ]
A. remember
B. realize
C. recognize
D. know
液压千斤顶的摇臂长度是（）。
A、固定的
B、根据需要确定
C、可以加长
