b. best
希望能帮到你,不明白还可以追问.
如有帮助,请采纳.首先谢谢你，请问这道题。。。。This maths problem is easy ______________.选择一项：a. worked b. to be working out c. to work out d. work outc. to work out 希望能帮到你，不明白还可以追问.如有帮助，请采纳.