谁发现了行星的椭圆轨道（）
A、牛顿
B、海什木
C、伽利略
D、开普勒
参考答案：D
The traffic rule says young children under the age of four and _____ less than 40 pounds must be in a child
safety seat. [ ]
A. being weighed
B. to weigh
C. weighed
D. weighing
