They are all working hard ( ) at English.A.on B.with C.at D.in -----------C请赐教,原题中无at

They are all working ____.. THEY ARE ALL WORKING HARD（改为同义句） They all are working hard on the farm 改错 They are working They are working 同义句 They are all working ____.A.good B.fine C.nice D.hard Check all parts to make sure they are working w____.首字母填空 All the students are busy .They're working hard for the （）exam. Check all parts to make sure they are working w_____.填神马? They are working.对They提问 though they are working in the air,they didn't feel cold at all.着句话对吗?有语法错误吗? Are they all right They are all right. Are they all right? where are they all People are all working hard.是什么状语? They are working hard.对working hard进行提问 They are all working hard ( ) at English.A.on B.with C.at D.in -----------C请赐教,原题中无at