be sure of：确信，肯定

be sure to do：一定，必定

have a corner on:垄断

lead......with:以......领先

consist of:包括（无被动形式）

salaried people:挣工资的人

a certain percentage of:一定比率

vary from：在某方面不同

vary in:在某一方面不同

eg:Mv vary widely in price.

that is:也就是说；既；换种说法

be due to：由于

owing to：由于（不能用作表语，放在句首或者句中）

eg:His illness was due to bad food.

be charged to sth

charge sb with sth：因......来指控某人

take charge of：负责，管理

figure out:算出来，想出来

in addition to：除了

in addition:另外

come in

complain about抱怨

eg:The people always complain about violent program on Tv.

spend on sth花费在某事

spend in doing sth花费在做某事

tend to 趋向于