A两句虽然都含有when引导的从句,但意义不同,用法也就不同.
前半句when he will come 是个含有when引导的时间状语从句,使用将来时,意思是我不知道他什么时候（将要来）
后半句是个含有when引导的条件从句,虽然是when,但从意思上理解是：当他回来时（他只要一回来）我就让你知道,所以是条件句,使用一个条件句的重要原则（主将从现）的原则.所以主句I'll let you know用了将来时,而从句but when he comes用了现在时.
一般现在时表示将来时46.I don't know when he ______,but when he ______,
1个回答
相关问题
-
I don’t know when he ____. But if he ____, I’ll ring you up.
-
I don’t know when he______ tomorrow .When he_____ , I’ll let
-
I don’t know when he
-
I don't know when he ____,I must talk to him when he____.
-
I don't know when he ____,I must talk to him when he____.(co
-
I don’t know when he _________ tomorrow.If he _________,I’ll
-
I don't know when he ＿（come）back.
-
l don't know when he_____
-
I don’t know _____ yesterday. A．when he will leave B．when wi
-
He ------- Beijing .I don't know when he did it.A has gone t