Mark the letter A, B, C or D to indicate the underlined part that needs correction in each of the following questions. 31. Although they always argue

Mark the letter A, B, C or D to indicate the underlined part that needs correction in each of the following questions.
31. Although they always argue with each other, but they are good friends.
A. always B. with C. but D. friends
32. My brother used to working downtown, but he moved to the suburbs three months ago.
A. working B. downtown C. moved D. suburbs
33. He didn’t have money to buy food because he has forgotten to ask his parents.
A. to buy B. because
C. has forgotten D. to ask
34. The scientists are investigating an area on Mars which liquid water may be found.
A. are investigating B. on C. which D. be found
35. If people use contaminated water for cooking, their health would be badly affected.
A. contaminated B. cooking
C. would D. badly affected