I was in the winter of 1951___a heavy fog moved into London.A.tha_英语解答

I was in the winter of 1951___a heavy fog moved into London.
A.that B.then C.when D.不填及每个选项的解释,

人气：395 ℃　时间：2020-06-14 17:44:07

解答

是不是把题目打错了.
It was in the winter of 1951 _____ a heavy fog moved into London.
答案为A.考查强调句.
是在1951的冬天一场大雾降临到伦敦.麻烦解释下强调句。。。谢谢了