to与and在下面有什么区别吗?It'simportanttotry[and]learnfromexperience.2、感觉下面的sometime是某个时间段的意思，为什么不用in？Everyoneexperiencestheseproblemsatsometimeintheirlives.每个人在人生的

Question

to与and在下面有什么区别吗?
It's important to try [and] learn from experience.
2、感觉下面的some time是某个时间段的意思，为什么不用in？
Everyone experiences these problems at some time in their lives.每个人在人生的某个阶段都会经历这些问题。

Answer 1

It's important to try [and] learn from experience.
 
    动词 go,come,try,write,see 等少数几个动词与其他表示目的动词连用时,可以有以下三种方式：
 
后面跟不定式动词（正式说法）,如：
 
　　He often went to visit the elderly persons of no family in the geracomium.他经常去探望敬老院的孤寡老人.
　　A lot of our friends came to see me.  我们的很多朋友来看过我.
　　Please writeto tell me what happened.请写信告诉我发生了什么.
 
用 and 并列两个动词（口语形式）
 
　　He often went and visited the elderly persons of no family in the geracomium.
　　A lot of our friends came and saw me. 
　　Please write and tell me what happened.
 
两个动词连用（非正式说法,等于第一种省略 to）
 
　　He often went visit the elderly persons of no family in the geracomium.
　　A lot of our friends came see me. 
　　Pleasewrite tell me what happened.
 
 2、感觉下面的some time是某个时间段的意思,为什么不用in?
 
   除了 in time（及时）和 on time（按时）外,time 前要求用介词at 表示某个时间点,如：
 
at a time (一次,同时,一下子,每次)
at all times （不论什么时候,老是）
at any time （随时; 无论何时）
at no time （永不...,在任何时候都不）
at odd times （在闲暇的时候,利用零碎的时间; 偶尔）
at one time （过去某个时期,曾经,一度）
at the same time （与此同时,但是）