一般在祈使语气或go和come的不定式之后不再使用目的不定式。常用Go and find Bill（去把比尔找来）来代替Go to find Bill；用Come and talk to Ann（来跟安说说话）来代替Come to talk to Ann。即：两个祈使动词用and连接起来时可代替一个命令+目的不定式。在一般情况下说：I must go and help my mother． 我必须去帮助我母亲。I’ll come and check the accounts． 我将来清理账目。而不是说：I must go to help my mother． I’ll come to check the accounts． 即：用and连接两个不定式结构来代替不定式+目的不定式结构。（参见第246节Ⅰ。）但如go和come用做动名词或以任何现在时态和过去时态出现时，应带一个表示目的的不定式：I’m thinking of going to look for mushrooms． 我想去采蘑菇。I went to help my mother． 我去帮助母亲了。I’ve come to check the accounts． 我来查账来了。I didn’t come to talk to Bill；I came to talk to you． 我不是来跟比尔说话的；我是来跟你说话的。