托福考试中的语法部分常常会有一些不显眼的意思相近小词作为考试知识点，总结一下考试前必浏览一下的几个小词组群，必会叫你事半功倍。
like / as
like 是介系词，需要接名词。
as 是连接词，需要接子句。
She sings like an angel.
She sings as an angel does.
due to / because of / because / for / since / as
due to 同意词，一般放在 be 动词之后。
His absence was due to illness.
because of 由于有介系词，需要同意词。
He canceled his reservation because of his cold.
because 作连接词，叙述理由，要接子句。
I don t go to school because I had a bad headache.
for 作连接词，推断前句的原因，要接子句，但不可以放在句首。
He was glad to go, for his grandmother had been good to him.
since 是连接词，语意没 because 那样强，置于句首。
Since you are going to go to the post office, would you mail this letter ? （既然你要去邮局，可以帮我寄这封信吗？）
as 作连接词，语意比 since 更弱。
As it was getting dark, we made for home.
compare to / compare with
compare to （比喻、比作），作抽象事物之间的比较，而 compare with 则作一般事物的比较。
I should compare your eyes to diamonds.
我应该把你的双眼比喻成钻石。
We can t compare diamond with jade1.
大家没办法比较钻石和翡翠。
imply / infer
imply 是暗示、暗寓的意思 ， infer 则是由暗示、暗寓来推断结论。
The guest speaker implied that the scholar s theory was wrong.
The fact may be inferred from his words.
watch / look / see
watch 是看着动态的景物， look 是看着静态的景物， see 则广义地用于看见人或物
I am watching a baseball game/TV.
Look at the picture on the wall.
I can see some roses in the vast.
scarcely /rarely /seldom / seldom, if ever / hardly ever
scarcely, rarely, seldom 和 hardly 放在句首时，主词和 be 动词或助动词要倒装。
seldom 和 rarely 是极少的意思，一般置于动词之前。
She had seldom [or rarely] written to her friend.
seldom if ever 和 hardly ever 是副词片语，意思皆为几乎不 . 。
He seldom, if ever, drinks.
He hardly ever drinks.
kind of
this kind of + 单数名词 = these kind of + 复数名词，都指只有一个类型。 these kinds of 才指有非常多种类
This kind of man is dangerous. = These kind of men are dangerous. （这种人非常危险。）
These kinds of trees are easy to grow. （这类品种的树比较容易长。）
by / till
by 表示将来将完成的某一时间界限。
｜｜ I will finish my paper by tomorrow.
目前 完成的时点
till 是表继续动作的终点
ˉˉˉˉˉˉˉˉˉˉ继续ˉˉˉˉˉˉˉˉˉˉˉˉˉˉ I will be here till tomorrow.
目前
线段终点
