近年来，人们致力于研发以电池为动力的纯电动汽车，期望更加节能环保、安全而高效，并取得了长足的进步，对于某成熟品牌的电动汽车，已知其质量恒为m，在水平路面上行进过程中所受阻力恒定（不计空气阻力）．

This one is ______ Amy.

要得到函数$f\left(x\right)=\cos \left(2x+\frac{\mathrm{\pi }}{3}\right)$的图象，只需将函数$g\left(x\right)=\sin \left(2x+\frac{\mathrm{\pi }}{3}\right)$的图象（　　）

完形填空。

    A boy and a girl catch a bird and 1 it in a birdcage (鸟笼）. They like it 2 and 3 it every day. A cat sees the bird and wants 4 her supper. 5 the bird is in the cage. She can't catch it. So she is very 6.

    One day, she opens the door of the cage 7 wants to catch it. But the bird flies away. The cat 8, and she has 9. The two children 10 and　see the bird isn't in. They are very angry and put the cat into the cage.

研究性学习在实验室进行了化学实验，向一盛有镁和铜混合物的烧杯中加入一定量的稀盐酸，充分反应后，观察到烧杯中有固体剩余，对反应后所得溶液中溶质的成分进行探究．