Question

Do you know if he ____to play basketball with me ? ---I think he will come if he ___free tomorrow.

A comes,is B comes;will be C will come, is D will come, will be

Answer 1

第一句话，if引导宾语从句，表示“是否”的意思，从句中谓语动词要用一般将来时，因此用“will come", 第二句话if引导条件状语从句，表示“如果”的意思，从句谓语动词用一般现在时，所以用“is",所以选C，下面列举了if 的用法，希望能好好看看，祝你进步。1. (表示条件)如果 ,主句用将来时，if从句用现在时表示将来
He will come if you invite him.
如果你请他,他会来的。
2. (表示虚拟)假如,要是
1）时态：可以表示过去，现在和将来的情况。它的基本特点是时态退后。
a. 同现在事实相反的假设。
句型 ： 条件从句 主句
一般过去时 should( would) +动词原形
If they were here, they would help you.

b. 表示于过去事实相反的假设。
句型： 条件从句 主句
过去完成时 should(would) have+ 过去分词
If she had worked harder, she would have succeeded.
The rice would not have been burnt if you had been more careful.
If my lawyer had been here last Saturday, he would have prevented me from going.

If he had come yesterday, I should / would have told him about it.
含义：He did not come yesterday, so I did not tell him about it.
If he had not been ill and missed many classes, he would have made greater progress.
含义： He was ill and missed many lessons, so he did not make greater progress.

c. 表示对将来的假想
句型： 条件从句 主句
一般过去时 should+ 动词原形
were+ 不定式 would + 动词原形
should+ 动词原形
If you succeeded, everything would be all right.
If you should succeed, everything would be all right.
If you were to succeed, everything would be all right.

3. 是否 = whether 连接宾语从句
I wonder if she is ill.
不知她是否病了。

Answer 2

正确：C
if表示“是否”时，从句时态必须据实际进行选择，第一个句中的if是是否的含义，从句体现将来时，故填will come; if 表示“如果”时，常套用“主将从现”，即主句使用一般将来时，从句使用一般现在时，故从句填is。

Answer 3

C
第一个是宾语从句，用将来时
第二个是条件状语从句，主将从现