例句：
They are playing basketball now.
现在，他们正在打篮球。
Listen， She is singing an English song.
听，她正在唱英文歌。
Look at the picture. The children are flying kites in the park.
看这幅图。那些孩子正在公园放风筝。
We are making model planes these days.
这些天我们在做飞机模型。
