The maths problem is so hard,I really don't know ____.A.how to do it B.how to do C.what to do

The maths problem is difficult,but f___we work it out. The maths problem is too difficult.math为什么加s The maths problem is wery easy.They can work it out=The maths problem is __ __ for ___ to __ ___急 The maths problem is not difficult.It is e___根据首字母完成句子 __ __ THIS MATHS PROBLEM IS ! It is difficult () out this maths problem The boy is very clever .He can work out such a maths problem without d＿. The Maths problem is very e______ .I can work it out mysulf.快 1.Is the maths problem ______?Yes,I can work it out______.(easy) 定语从句改错：This is the most difficult maths problem which I have done. The maths problem is too difficult for him to work out.(改为复合句)怎样变复合句? 改错the maths problem is so easy that i can work out the maths problem isn't very easy and it is difficulta to finishb to finish it 亲们 急用!working out the maths problem is very easy.(改为同义句) the boy is young ,but he can work________the difficult maths problem(填介词） It is _________(possible)for the little child _________(correct)the________(correct)maths problem ________(correct). Lily is working ___ the maths problem.A.at B.in C.on D.of somebody worked out the maths problem.改为否定句( ) ( ) out the maths problem.