英语中not.but后跟动词的用法：就是but后面跟不跟to的问题，有个口诀，前有do，后省to，就是说，如果前面有了do，则but后直接跟动词原形。
not.but的例句
1. "Will it happen again?"— 'I hope not. but you never know.'
“这事还会再发生吗?”——“但愿不会，但谁知道呢。”
2. She could not but congratulate him.
她只能祝贺他。
3. He is extremely strong — not but that he will catch cold at times.
虽然他特别健壮,可是有时也会感冒。
4. A poet could not but be gay in such a jocund company.