Question

but用于be动词后什么意思

Answer 1

1 .当but前的谓语含有实义动词do(可以是各种形式)时,其后的不定式通常不带to：
She will do anything but play chess.她除了下棋外什么都愿干.
He did nothing all day except watch TV.他一整天除了看电视什么也没做.
2.当but前的谓语没有某种形式的实义动词芹洞do时,其后的不定式通常要带to：
They had no choice but to obey.他们别无选择只有服从.
He wanted nothing but to stay here.他除瞎悔了想呆在这里外,其他什么也不想.
3.在cannot (help) but后习惯上接不带to的不定式：嫌神枯
I cannot (help) but admire his courage.我不得不佩服他的勇气.
你可以对照看了.