这个句子为什么要用不定式the test potential is to be increased to the test voltage不能说成The test potential increased to test voltage吗?

这个句子为什么要用不定式the test potential is to be increased to the test voltage不能说成The test potential increased to test voltage吗? 为什么这个句子情态动词后面可以用不定式?The doctor did what he could to save the girl who was badly hurt in the accident. She doesn't konw whether to go or wait.这个句子中为什么要用动词不定式（to go)? 不定式做定语与不定式做补语的区别!The Chinese government has the America government to work out some affairs international.这个句子中的不定式to work out... 是做定语还是补语,要怎样区分? who did best in the history test in the class?who did the best in the history test in the class?这个句子表达对还是who did best in the history test in the class? I have to do the homewoek 这个句子中的不定式做什么成份?求解答 I will go to see you.这个句子中的to是介词,还是动词不定式?为什么? 句子中什么时候用不定式? 为什么补考用take the test later而不用late 不定式的作用,在下面这句话的作用.they thought of the idea to cycle along the Mekong River. 其中的TO CYCLE ALONG 的动词不定式有什么作用啊,为什么要用不定式 什么时候句子开头用不定式和动名词形式请看例句； to swim in the lake is liked by everyone 为什么开头用不定式?还有什么时候开头用不定式,什么时候用动名词.我查百度上说动名词表原因,不定式表 The microscope is rather difficult (to rapir)为什么要用不定式?是因为is后面跟表语么...然后不定式作表语? 老师,请问英语中在什么情况下使用不定式?比如The boy to write this letter needs a pen“为什么要用不定式to write呢 ? 不定式 动名词的状语是句子的状语吗 那为什么又说不定式 动名词的状语要和不定式动名词看作一个整体吖 如果动词不定式的逻辑主语是这个不定式所表示的动作的承受者,不定式一般要用被动语态形式.既然这样,为什么“This is a place to visit”不用被动 It is+adj+of+n/pronoun+to+v,用括号中的提示词,加上for,enough或of完成句子,将动词改写成不定式形式Stella:I wonder who got the top mark in the test.I'm sure it was Tommy.He's (1)hard-working enough to get the best mark.(hard-work 麻烦讲解一下这个英语句子I ‘ failed the math test.这句话的意思是我的数学测试不及格,既然是我的,为什么不用my而用I呢?还有这个句子结构是什么,老师说是主谓宾,“I”是主语,“failed”是谓语 英语1.The first thing you must do is ___________the teachers before class为什么要填动词不定式而不能用动名词?2.一个句子在开头划线,如何选择是填动名词还是动词不定式?请举个例子