在行驶中,把变速杆换入一档,汽车的()。
A.行驶速度慢,牵引力小;
B.行驶速度快,牵引力小;
C.行驶速度慢,牵引力大;
D.行驶速度快,牵引力大
参考答案:C
—What's your father doing now?
—He ____ the room.
A. cleaned
B. cleans
C. has cleaned
D. is cleaning
冷芯盒用树脂的储藏温度要求为()℃。