You should exercise at least thirty minutes a day.

你每天应该至少锻炼三十分钟。

同一单元的其他句子

• How often do you exercise every week?你每周锻炼几次？
• I usually exercise three times a week.我通常每周锻炼三次。
• She hardly ever eats junk food.她几乎不吃垃圾食品。
• Do you often go swimming on weekends?你周末经常去游泳吗？
• He always runs in the morning before school.他总是在上学前早上跑步。