if什么意思、怎么读？单词用法、记忆法、发音音标、反义词同义词辨析、释义

We still don't know whether if it's a boy.
我们还不知道宝宝是不是男孩。


You must sharpen your pencil if you want to use it.
如果你想用铅笔的话，要先削尖它。


A hostess will help you if you have any problems.
如果你遇到任何问题，空姐会来帮你的。


Don't get closer to radiation if you are not in protective suit.
没有穿防辐射服就不要靠近。

If you really need help then go ahead and ask.

你如果真需要帮助，那就请人帮助吧。

※Freedom is the freedom to say that two plus two makes four. If that is granted, all else follows.——Ceorge Eric Blair Orwell.British novelist  自由是指人们有说“2+2=4”的自由，有了这一保证，其他一切便会随之而来。英国小说家奥韦尔 .G.E.B.  
※No one can degrade us except ourselves; that if we are worthy, no influence can defeat us.——B.T.Washington, American educator除了我们自己以外，没有人能贬低我们。如果我们坚强，就没有什么不良影响能够打败我们。美国教育家   华盛顿 B T
※Knowledge is a comfortable and necessary retreat and shelter for us in an advanced age; and if we do not plant it when young, it will give us no shade when we grow old. 学识可使老年时舒适地退隐和有所寄托；但如果年青时不使它扎下根，老年就得不到它的庇护。
※If it is not right, do not do it; if it is not true, do not say it. (If it is not broken, do not fix it.) 不正确的事不做，不真实的话不说。