为了克服时差效应。白天向东跨时区飞行后应进行（）.
A.良好的夜间睡眠
B.良好的昼问睡眠
C.上午小睡，下午大睡，当晚早睡
参考答案：A
预防矫治系从何时开始的（）
A.自胚胎第3周
B.自胚胎第4周
C.自胚胎第5周
D.自胚胎第6周
E.自胚胎第7周
A football match between Class Two and Class Three ________tomorrow afternoon.[ ]
A. is held
B. was held
C. must be held
D. will be held
