为了减少动力消耗,气动传感器的输出为()信号。
A.化学力
B.长度
C.分子力
D.低压
参考答案:D
As we all know, apples are sold by ____ weight, and socks are sold by _______dozen.
A.the; a
B./; a
C./; the
D.the; the
正常人50岁左右时,角膜内皮细胞的平均密度为每平方毫米
A.3000~4000个
B.2150~2400个
C.2000~2500个
D.1000~1500个
E.2600~2800个