1、 How long和how often
[误] I have been studying long for the exam. [正] I have been studying for a long time for the exam.
解释： long用作表达时间的副词时，在否定句及疑问句中最常用，但在肯定句中除与so, too, as…as连用外，一般要用for a long time.
[误] I'll call you as long as the book will be returned. [正] I'll call you as long as the book is returned.
解释： as…as引导的状语从句中可以用一般现在时表示将来。 区分as long as 和as soon as.
[误] How long do you go to see your parents? Once a week. [正] How often do you go to see your parents? Once a week.
解释 ： 因为答语为每周一次所以问的是频率，要用how often. How long 是问时间长度的
2、 look 和 find
look for 侧重于 "寻找"这个动作，不关注有没有找到的结果，如： What are you looking for?
而find则侧重于结果，注重已经发现的事物或者现象，如： It is very difficult to find a job. 这里不能用look for，因为真正困难的是"找到"工作。
(1)He often looks back on his high school days. 解释 ： look back on something 为"回顾"、"回想，字面意思“向回看”，真实意思是回顾回想过去的事物
(2) I wish you wouldn't look down on (upon) the children's work.
look down on (upon) 为"看不起"某人或某事。
(3)希望，期望look forward to doing ······
[误] I'm looking forward to see you.[正] I'm looking forward to seeing you.
look forward to词组中的to是介词，所以其后要加名词或动名词，不能接不定式。
3、 lot 和 little
(1)因为我有足够多的钱，所以我可以现在就买这本词典。[误] I can buy this dictionary now, because I have got much money.[正] I can buy this dictionary now because I have got a lot of
解释 ： much money多用于疑问句与否定句中，而在肯定句中要用a lot of. lots of与a lot of之间无多大区别，两者都可以修饰可数与不可数名词，所以常常可以互换。
(2)他现在高兴多了。[误] He is more happier now. [正] He is a lot happier now.
解析： 不可用more来修饰比较级，能修饰比较级的词有very much, a lot, lots, any, no, rather, a little, a bit等。
3、 make 和 do
(1) 这个小男孩被要求复述这个整完的故事。[误] The little boy was made repeat the
whole story. [正] The little boy was made to repeat the whole story.
(2)父亲让他的儿子从早到晚做作业。[误] The father made his son to do his homework
from morning till night. [正] The father made his son do his homework from morning till night.
解释 ： make 的句型为"make somebody do (doing) something".但在被动语态中原来被省去的不定式符号to要被还原回来。
(3)我时常犯这个错误[误] I always do this mistake. [正] I always make this mistake.
解释 ：英语中do和make是十分不易弄清的两个动词，do常用于谈论工作时或某种不确定的活动时，如： do a favor(帮个忙)，do one's best(竭尽全力)，do good(有益)， do harm(有害)，而多数情况下常用make, 如： make a suggestion, make a cake, make a bed(收拾床)，make a noise, make money等等。
(4)make form/ of ,由什么制作而成 [误] This wine was made of grapes.[正] This wine was made from grapes.
解释 ： 当成品制成后，其原料的性质有所改变时应用make from，否则用make of， 如： This door was made of iron.
(5)辛勤工作可以弥补缺陷的智力 make up for ,弥补···
[误] Hard work can often make up a lack of intelligence.[正] Hard work can often make up for a lack of intelligence.
解释： make up是"创造"、"编织"，而make up for是"弥补……的不足之处"。上句应译为"勤奋工作可以弥补天资的不足。"
(6)下定决心做某事···[误] We made up our mind to study hard.[正] We made up our minds to study hard.
解释 ：mind这里是可数名词，使用要特别予以注意make up one's mind是"下定决心"之意。
(7)由什么组成make up of ·····[误] Our class is made of twenty girls and twenty-one boys.
[正] Our class is made up of twenty girls and twenty-one boys.
解释： make up of…是"某物由……组成或构成"。