17. The girl lost her balance and fell off the balance beam.
小女孩失去了平衡，从平衡木上摔了下来。
18. She rolled the socks into a ball.
她把袜子卷成一团。
19. How did you enjoy the ball?
你们在舞会上玩得高兴吗?
20. A band of robbers held up the train.
一群强盗抢劫了火车。
21. The town stands on the left bank of the river.
城镇位于河的左岸。
22. He has a large deposit in the bank.
他在银行有大笔存款。
23. The organ has two banks of keys.
那架风琴有两排键盘。
24. Clouds are banking up.
云层正在堆积。