进行环境毒物的致突变试验，是观察毒物的（）。
A.急性毒性
B.慢性毒性
C.远期危害
D.蓄积毒性
E.间接毒性
参考答案：C
It was________ his car after drinking that resulted in the terrible accident doing much damage to his car.
A．due to his driving
B．his losing control of
C．because he drove
D．to lose his control of
总图是指表示一台完整机器的（）
A、零件图
B、部件图
C、装配图
D、视图
