【初三英语从句】I don't know if he ______(come) back,if he _______(come) back ,please let me know.请问这种两个if在一起的题目怎么做啊?

英语；I don't know 【初三英语从句】I don't know if he ______(come) back,if he _______(come) back ,please let me know.请问这种两个if在一起的题目怎么做啊? 英语宾语从句语法I don't know who you are.为什么不用I don't know you are who 也是陈述语序啊 初三英语宾语从句问题,1.我想问特殊疑问句做宾语从句时,从句的语序是什么,我的英语老师说是主+谓 例：I want to know what you were doing at that time.可是我在练习上又看到了另一种：I don't know how t I don't know. I don't know how I could repair the bike.此句I don't know后跟的是什么从句? 宾语从句I don't know what is his name 还是 I don't know what his name is? “i don't know you know i don't know I know it that classmates don't know.是一个宾语从句吗? Dose the enigineer know french?(I don't know)改为宾语从句 宾语从句:I don't know what they looking for .及物动词宾语从句:I don't know what they looking for .及物动词指什么? i don’t know the rason why he looks unhappy today 定语从句 拆分句子i don’t know the rason why he looks unhappy today拆分成两个句子帮一下我谢谢在线等各路英语高手加油 宾语从句的否定形式i don't think i know you能不能写成i think i don't know you如果不能为什么? I don't know Chinese 翻译英语谢谢 sorry,I don't know. i don`t know much I don't really know. I don't know miss