Jack often watches TV _______________ ( 直到半夜 ). 2. Sleeping helps us grow __________________ ( 更高更强壮 ). 3. If teenagers want to __________ ( 保持健康 ), they should get enough sleep every day. 4. I usually ________________ ( 散步 ) after supper. 5. Which sports do you like better, __________ ( 打网球 ) or __________ ( 骑自行车 ) ?