A:0.9
B:3.17
C:14.5
D:464.6
When do you ________ every day?
According to the air traffic rules, you ______ switch off your mobile phone before boarding.
利用显微镜观察人的血细胞涂片,在两种不同的放大倍率下,视野分别为甲和乙,如图所示.下列相关叙述正确的是( )