“sit down”是一个祈使句还是一个短语呢?

“sit down”是一个祈使句还是一个短语呢? you can sit down.改为祈使句 She should sit down的祈使句 you can sit down here.改为祈使句 是sit down at the table还是sit down beside the table 怎样判断一个短语是分词短语还是动名词短语? please,sit down中的down是介词还是副词?为什么会出现sit down on one of these 这句话的前半分是一个句子还是一个短语呢? 是he had sit down还是sat?为什么 Sit down,please的回答是OK还是Thank you You can sit down and have a rest改为祈使句 You can come in and sit down.(改为祈使句)