hours and hours前接的介词

March 5th前要加什么介词,还有7p.m前的介词,以及 it lasts ( ) three hours.括号中填 And they often study_____long hours. two hours and a half BUSILESS HOURS的意思 We studied_______about two hours.介词填空 three and a half hours的近义词,急用! two and a half hours这种结构的构成 one and a half hours 的同义词组 "two and a half hours" 有什么相同的句子? 不是说表示半小时的时候,half前加a吗?如one hours and a half 或one and a half h In the evening,I watch TV ( ) about two hours.(用适当的介词填空） i often fish for hours without cathing anything介词和后边的短语做什么成分