如果每个人都为保护环境做出自己的贡献 If everyone -----a contribution to protect the environment.
问题描述：
如果每个人都为保护环境做出自己的贡献 If everyone -----a contribution to protect the environment.
答
makes
make a contribution to do sth
做贡献
答
did
does
答
应该是If everyone makes a contribution to protecting the environment.make a contribution to结构中to是介词