()离合器可以使同一轴上具有两种不同速度。
A.侧齿式
B.内齿式
C.摩擦
D.超越
参考答案:D
DNA多聚酶的功能
A.DNA合成
B.解开DNA双链
C.消除DNA螺旋
D.连接DNA片段
E.保持DNA合成区单链的稳定
—Excuse me. Do you know _________?
— Last Sunday.
A.where he would like to visit
B.when he was back home
C.how he came here
D.why did he come to the zoo