Time must be a valid time of day

Time must be a valid time of day Students must spend a lot of time ______ every day.A.studyin is not a valid date and time Time must be made use __ English.A.of to learn B.of learning 翻译：And it will be summer at this time of a day. It will be summer ______ this time of day. He's s_______to be here at this time of day I made ( ) a condition that everybody must be on time. 在一天不同的时间 different time in a day 还是　different time of a day at this time of day （）【plan】 an Open Day takes a lot of time. You must be come to the meeting on time I___ A.must B.have t