英语短语填空帮忙下谢谢`````

英语短语填空帮忙下谢谢`````
keen,sssyme,courteous,take into account,center on,be based on,
sentimental,mutual,matual,matter,strike up,in contrast with,leave off
1)The trouble was that many of his friends were also____observers of life
2)The policeman ___a conversation with John while they were waiting for the bus.
3)We kept the old photograph for purely____reasons.
4)Scientists___that there is no animal life on Mars.
5)This song ___an old folk tune
6)This is the normal___manner of introduction among speakers of American English.
7)We usually see eye to eye on the things that really___
8)Her research___the social effects of unemployment
9)A family has __affection when each person likes the others and is liked by them
10)When judging his performance ,don't __his age ___.
11)___their system,ours seems very old-fashioned.
12)He ___sobbing at last ,and dried his eyes with his handkerchief