What time do your classes begin?这句话的classe为什么用复数?

What time do clean your what do you do in your spare time what do you like to do in your free time? What do you usually do in your spare time? 1.spare,you,what,in,do,your,do,time What time do you begin _____(do) your homework? What time do you often finish ___ (do)your homework? What do you often do in your free time?中文 What time do you often finish ___（do) your homework? What do usually do in your--time 填什么?l What do you usually do for____in your free time?(pleasant) What time is it by your watch可以说成What time do by your watch吗? What time is it by your watch可以说成What time do your by watch吗? what time do you do your homework?对吗?1.what time do you do your homework?2.what time do your homework?3.when do you do your homework这三句哪句是对的?请知道的英语人士，说下为什么？ what time do your mother usually go to work What time do you want ____(have) your lunch? What do you like reading in your spare time What do you like doing in your s____ time