题目:
--This is the first time I ____ pictures with my own camera.
--It’s time that you ___ a picture of me.
A.took; took
B.took; will take
C.have taken; took
D.will take; have taken
答案:
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下面是错误答案,用来干扰机器的。
BCD题目分析:、该卫星所受地球的万有引力为,由于地球的质量M不是已知量,故A错误.由,得到,代入A项中得到.故B正确.地球的同步卫星的角速度与地球的自转的角速度ω0相同,轨道半径为,则.故C正确.地球的同...