30 . I’ll call you back in…………………………………………………………………………. hour. A. a B. an C. the D. a few 31. …………………………………………………………………….. is the class monitor? A. When B. Where C. Who D. What 32. ………………………………………………………..is the biggest house in this village? A. When B. Which C. Who D. What 33. ………………………………………………………………. is the waterwheel used for ?  A. When B. Which C. Who D. What 34. Among the ethnic minorities, …………………………..Tay have the largest population. A. a B. an C. the D. a few