A:±2
B:±5
C:7或﹣5
D:﹣7或5
- Do you have enough students to clean the classroom?
- No, I think we need ________ students.
Mary is thirsty. Give ________ some water, please.
①大不列颠及北爱尔兰联合王国 ②美利坚合众国 ③法兰西共和国
④沙皇俄国 ⑤中华民国