外径千分尺的（）可使测量时保持恒定的测量力。
A.测力装置
B.测徽装置
C.锁紧装置
D.隔热装置
参考答案：A
The little boy is dirty from head to foot because he ___ in the mud all morning.
A．has played
B．is playing
C．has been playing
D．was playing
下列哪种物质参与胆固醇的酯化过程（）
A.LPL
B.HDL
C.LDL
D.LCAT
E.HMGCoA
