小测验：选择正确的单词

1. The earth had been churned up by the wheels of the tractor.
   拖拉机轮子把泥土掀了起来.
2. Change the left wheel of Mr. Green's car.
   把格林先生车子的左轮换掉。
3. You can rotate the wheel with your hand.
   你可以用手转动轮子。
4. Let's have another look at the fly wheel.
   让我们再检查一下飞轮。
5. The waiter wheeled in a sweet trolley.
   侍者推来了甜点车。

　2个名词解释