Behind the department store there used to ______ much waste, _______?

A. have; usedn’t it            B. being; usedn’t there  C. be; usedn’t it         D. be; usedn’t there

-- __ behind the door?

    --No, they aren't.

     A. Where are          B. What's         C. Are those keys  D. Is the key

Behind bad luck comes good luck. So something good happened _____ you..

A. in       B. to       C. for       D. with

Behind the department store there used to ______ much waste, _______?