要取得良好的演讲效果，演讲者需要做的工作有（）。
A.充分准备
B.语言得当
C.保持与听众的平等
D.盛气凌人
参考答案：A, B
— My English isn't good.
— How many years ago ____ English? [ ]
A. did you began to study
B. do you begin to study
C. have you studied
D. had you studied
下列哪个因素与哮喘发病无关？（）
A.病毒感染
B.过敏原
C.气管扩张
D.气道高反应性
