为什么at five thirty,不用连字符,而twenty -four hours用连字符?

为什么at five thirty,不用连字符,而twenty -four hours用连字符? She must be at least thirty-five years old.In my opinion she() a.has b.is c.must 为什么? my mother often goes home at five thirty同义句 GO,IN,I,AFTERNOON,AT,HOME,THE,THIRTY,FIVE Tom usually gets up at five thirty 对at five thirty 提问＿ ＿ ＿ Tom usuallp ＿ ＿ The Lis( )dinner at five thirty every day.The Lis——（have）dinner at five thirty every day. 5:35为什么不说是twenty-five to six 而是thirty-five past five? five thirty-five的意思 five thirty-five翻译汉语 five thirty-five的中文 thirty-five years old中five和years 之间不用加连字符吗?一般不是说thirty-five-years old 吗? thirty past five【是什么意思】 thirty five序数词 There are thirty-five thirty-five hamburgers是什么意思 thirty-five单词是什么意思 thirty five的过去式 His work ______(finish) at half past five.中间为什么不用被动语态?