33.In the past few years,traffic problems (become) ________ more and more serious.
问题描述：
33.In the past few years,traffic problems (become) ________ more and more serious.
填were becoming
答
have become （过去完成时态）
翻译：在过去几年,交通问题越来越严重了.填were becoming 不对吗？不对，were becoming 是过去进行时态。是过去某一时间，正在进行。好的，明了了，这里是一段时间，谢谢你，达人。