1. 當and或or連線兩個並列不定式時，第二個to常省。
I plan to call him and discuss this question.
My friend in China asked me to telephone or write to her in my freetime.
我中國的朋友讓我有空給她打電話或寫信。
2. 當兩個並列to有對比意義，第二個to不能省。
I haven’t decided to stay at home or to travel to Beijing this holiday.
我還沒決定假期是待在家裡還是去北京旅行。
To be, or not to be, that is the question.
生存還是毀滅，這是一個值得思考的問題。(《哈姆雷特》)
3. 當兩個to之間無並列連詞，to不可省。
I came here not to help you, but to fright you.
我來這不是為了幫你，而是為了嚇唬你。
4. 當三個或以上帶to不定式構成排比，所有to不可省。
Read not to contradict or confute; nor to believe and take for granted; notto find
talk and discourse; but to weigh and consider.
1. 當and或or連線兩個並列不定式時，第二個to常省。
I plan to call him and discuss this question.
My friend in China asked me to telephone or write to her in my freetime.
我中國的朋友讓我有空給她打電話或寫信。
2. 當兩個並列to有對比意義，第二個to不能省。
I haven’t decided to stay at home or to travel to Beijing this holiday.
我還沒決定假期是待在家裡還是去北京旅行。
To be, or not to be, that is the question.
生存還是毀滅，這是一個值得思考的問題。(《哈姆雷特》)
3. 當兩個to之間無並列連詞，to不可省。
I came here not to help you, but to fright you.
我來這不是為了幫你，而是為了嚇唬你。
4. 當三個或以上帶to不定式構成排比，所有to不可省。
Read not to contradict or confute; nor to believe and take for granted; notto find
talk and discourse; but to weigh and consider.