两台铲运机平行作业时，机间隔不得小于（）。 A.2m B.1m C.3m D.2.5

The nurse preparing to give a child an intramuscular injection chooses to give the injection into the gluteal muscle. The site is acceptable because which of the following reasons

A. The child has been walking for 1 year.
B. The child has small deltoid muscles.
C. The child is older than 2 years.
D. The child weighs more than 25 pounds.

-----What’s your hobby?

-----I _______ listen to music, but now I enjoy dancing.

A. am used to   B. used to  C. am used

在多聚酶链式反应扩增DNA片段中，DNA合成方向是[ ]

A．从子链的3′端向5′端延伸

B．从引物的5′端开始延伸

C．从子链的5′端向3′端延伸

D．以上皆可

两个数的商是0.28，被除数和除数同时缩小到原来的十分之一，商是______；如果除数扩大到原来的10倍，被除数不变，商是______．

电池扳手为静扭工具，最终扭矩由人来承受，使用时应握紧以免扭伤手臂。