53.  The contributions of African Americans to US musical history began with the arrival of the first Africans on its mainland in 1619.

52.  I am worried by all the violence in the novels. I wonder why everything has to be dealt with by fighting and killing.

51.  e do quite a lot of experiments in the science lab to help us better understand our textbooks of physics, chemistry and biology.

50.  We’d better remove the big stone on the road, for it’s in the way.

49.  He’s broken his leg and needs an operation  immediately.

48.  The art school holds an art exhibiton every year, where students’ paintings and drawings are shown.

47.  ---Do you say you like the shirt over there?

…Not exactly . I said it’s not bad.

46.  It’s kind of you to do me the favour to carry my bag. 

45.  This song is becoming widely popular in schools.

44.  The last month of the year is December。