首先在语义上，provide仅表示“提供”，而offer强调“主动提供”。
其次在语法和搭配上，offer后可跟双宾语，而provide后不可跟双宾语
最后在搭配上，offer可组成词组offer sb. sth./offer sth. to sb.；provide可组成短语provide sb. with sth./provide sth. for sb.
have been意为“成为……多长时间”；have been in意为“在某地呆了多长时间”。二者都常与表示一段时间的状语连用。如：
1、She has been a teacher for five years。
2、I have been here for two hours。
3、His parents have been in China for three months。
have been to意为“曾经去过某地”，现在已不在那里了，常与ever,just,never等词连用。其后可接once,twice等表示次数的词。如：
4、He has just been to the library。
5、They have never been to the Great Wall。
6、I have been to Beijing many times。
have gone to意为“到某地去了”，说话时作句子主语的人不在现场，通常是第三人称作句子的主语。如：
7、Whereis Tom? He has gone to the post office。
8、Mr Green isnt here。He has gone to Shanghai。
