Jim works hard at his lessons.He doesn't want to ____.A.let down his parentsB.let down usC.let his parents sadD.let his parents up

jim wants to get good grades in the math exam so he works hard at it.为什么用介词 at? A_____ my grandfather is seventy years old,he is healthy.Jim works hard.He always gets high g_____ at school. Jim works hard at his lessons.He doesn't want to ____.A.let down his parentsB.let down usC.let his parents sadD.let his parents up 选哪项?为什么?Jim works hard at his lessons.He dosen't want to______A.let down his parentsB.let down usC.let his parents sadD.let his parents up Jim works __,but his brother ___works.A.hard,hard B.hardly,hardly C.hard,hardly D.hardly,hard she works hard at English的同义句谢谢了, Bob works hard at English.(改为同义句) Neither you nor she works hard at English. his brother works hard at his lessons.(改为一般疑问句) Amy works hard at school.改为一般疑问句） At school Joe works hard and does well in (). school,hard,at,works,she该怎么拼 school,hard,at,works,she该怎么拼 yao ming works hard at playing basketball是什么意思? He works( )French.A hard B hardly C hard at D hardly at Jim studies ___ 22:00 every day.He works very hard. It is __(usual) for jim to pass the exam because he never works hard. She good at ping-pong at PE.还是She is good at ping-pong at PE.She works hard at chinese.还是She is works hard at chinese.