41. in a word, in words

　　in a word总之，一句话， in words口头上 In a word, you are right.

　　42. in place of, in the place of

　　in place of代替，in the place of在…地方 A new building is built in the place of the old one.

　　43. in secret, in the secret

　　in secret秘密地，暗自地，偷偷地，一般用作状语；in the secret知道内情，知道秘密，一般用作表语 My mother was in the secret from the beginning.

　　44. a girl, one girl

　　a girl可泛指所有女孩, one girl一个女孩 Can one girl carry such a big box?

　　45. take a chair, take the chair

　　take a chair相当于sit down坐下，take the chair开始开会

　　46. go to sea, by sea, by the sea

　　go to sea当海员，出航，by sea乘船，由海路， by the sea在海边 go by sea

　　47. the doctor and teacher, the doctor and the teacher

　　the doctor and teacher指一个人，既是医生又是老师，the doctor and the teacher两个人，一个医生和一个老师 the doctor and teacher is

　　48. in office, in the office

　　in office在职的，in the office在办公室里 He is in office, not out of office.

　　49. in bed, on the bed

　　in bed卧在床上，on the bed在床上 The book is on the bed. He is ill in bed.

　　50. in charge of, in the charge of

　　in charge of管理，负责照料， in the charge of由……照料 He is in charge of the matter. The matter is in the charge of her.

　　51. in class, in the class

　　in class在课上，in the class在班级里 He is the best student in the class.