—When Mum is at home, I have to practice every day, but she is on a business trip this week.
A:How often
B:How about
C:How much
D:How long
有位同学在暑假里这样安排学习活动:早晨记忆好,就背一些唐诗宋词;上午和下午整块的时间就用来做语数外;闲暇时就看一看《哈利波特》等有趣的小说;饭前就看一看报纸。他这样做( )
①提高了学习效率 ②科学安排了时间
③学会了自主学习 ④是书呆子的表现
As is known to us all, taking exercise is b____ to our health.