题目

It is morning，_______ the birds are singing． A. since                B. for              C. because              D. as 答案：B直接写得数． 40×3=500×2=400×5=75÷8=200-178=210×4=789×0=389+470=302×3=25×4=16×2=27÷9=65-7=760+0=103×5≈299×4≈6×7+8=39+29=27+57=1-23=1212-38+18=