he want to know if you need help? 请问if在这里是什么从句?

i want to know if he ___(come) yesterday. he want to know if you need help? 请问if在这里是什么从句? I want to know _____ he will come tomorrow为什么是 if 而不是 when I want to know if he still works in the factory. want to know if he needs any help请问这的if为社么是“是否”而不是如果? 请问if引导的宾语从句前的to know是个什么成分?I want to know if he will go to the park with us We want to know when he ____ from Taiwan.If he ____,please tell us.(return) 时态填空 What do he want to know?改错 I want to know __ he is tall.A.that B.if C.how D./ 翻译并语法说明 Just now Tom______ （give）me a call.He ______(want)to know if I_____(go)with them this Saturd. what i want to know is_ he likes the gift given by us.a.thatb.if c.whetherd.不填 what i want to know is ——he likes the gift given by usthat if whether / i want to know if he--- to visit the Expo 2010.if he---,i want to go with him.A、will go;will goB、will go；goseC、gose;goseD、gose;will go if you want to know the time,you look I want to know if you ever loved me? If you want to know something about lions and monkeys If you want to stay,let me know,____ I want to know if it ____(not rain) tomorrow