Ifhe_____thestorekeeper‘sscissors，hewouldhaveforgottentobuyapair.
B
本题测试的是虚拟语气的用法，其中的条件从句用过去完成时 had done，主句 谓语用 would/couldmight have+done.
Children who are over-protected by their parents may become_____.
_____youunderstandthisrule，you‘llhavenodifficultyindealingwithsuchproblems.
My wallet is nowhere to be found.I_____it when I was on the bus.
His article is better than_____in the class.