高一英语非谓语动词高手请进

问题描述:

高一英语非谓语动词高手请进
whether----,we will have a picnic tomorrow.
A.permitB.permitsC.permittedD.permitting
----carefully,this letter is very beautiful.
A,type B.typing C.typed D.to typed
请问什么时候用过去分词,什么时候用-ING形式?谢谢

选D,省略if的句子,允许的逻辑主语是天气,所以是主谓的关系,天气允许,所以是doing的形式,第二个是被打印,所以是be done