[英语]He has to be in bed____ten o'clock

[英语]He has to be in bed____ten o'clock The students have to be in bed____ten o'clock at night.A.UNT he has to be ____ bed ___ nine o'clock A、at;at B、to;by C、in; 自学英语求解答.He has to be home before six o'clock.be在这里的用法和作用? 外语：连词成句（1)has,by,in bed,she,to,ten,o`clock be She has to be in bed by ten o'clock He has to get up at six o'clock对at six o'clock提问 He has to go home ____ 6 o'clock.A in B after C later D behi I have to be in bed by ten o'clock. He has to get to the station_______8 o'clock ,or he' He has to go to bed b__ nine o 'clock.Please r____ to bring Your baggage has found,takes three o'clock to be able to arr