问题：
试题 题型：未知 难度等级：
单项选择。 — Are you free this afternoon?— No, I'd like to te
单项选择。
— Are you free this afternoon
— No, I'd like to teach the children the piano (钢琴)
[ ]
A. playing
B. what to play
C. play
D. how to play
试题 题型：未知 难度等级：
单项选择。 — Are you free this afternoon?— No, I'd like to te
| 单项选择。 |
| — Are you free this afternoon — No, I'd like to teach the children the piano (钢琴) |
| [ ] |
| A. playing B. what to play C. play D. how to play |
参考答案：