托福語(yǔ)法指導(dǎo)：had better表示

had better表示""，相當(dāng)于一個(gè)助動(dòng)詞，它只有一種形式，它后面要跟動(dòng)詞原形。例如：
    It is pretty cold. You'd better put on my coat. 天相當(dāng)冷。你穿上我的外套。
    She'd better not play with the dog. 她不要玩耍那條狗。
    had better have done sth表示與事實(shí)相反的結(jié)果，意為"本來(lái)".例如：
    You had better have come earlier. 你本該來(lái)得早一點(diǎn)。