half an hour ago 什么意思?

half an hour ago 什么意思? half an hour? 什么意思? About half an hour ago.中文意思是? when ()it ()?(arrive) half an hour ago Sam ( )here half an hour ago Sorry,I ordered my food half an hour ago.对“half an hour ago” Half an hour =什么? I have waited for you since half an hour ago 此话成立吗,意思是? in half an hour's time什么意思 He was here().A.half an hour before B.half hour ago C.half a half an hour 和a half hour有什么区别? When did the train ___ Half an hour ago