第 68 课: 复习第六部分-3

Both people are singing. 两个人都在唱歌

Neither of these people is singing. 两个人都不在唱歌

Only one of these people is singing. 这些人中只有一个在唱歌

All six of these people are singing. 六个人都在唱歌

The father and his sons are digging. 爸爸和两个儿子在挖地

The father and his sons were digging. 爸爸和两个儿子刚才在挖地

The dog is looking at the book. 那只狗在望着那本书

The dog was looking at the book. 那只狗刚才望着那本书