if的時(shí)態(tài)比較多,但中考一般只考如下的：
if 如果,引導(dǎo)條件狀語從句,當(dāng)主句是一般將來時(shí),if引導(dǎo)的從句要用一般現(xiàn)在時(shí),如：If it doesn't rain tomorrow,I will go to the zoo.如果明天不下雨,我要去動(dòng)物園
if 是否,引導(dǎo)賓語從句,不受世態(tài)的限制,所以可以用一般將來時(shí),如：I don't know if he will visit his grandparents.我不知道他是否會(huì)去拜訪他的祖父母
if 還可以用在虛擬中,如：If I were you,I would travel around the world.如果我是你的話,我可以周游世界.