Question

________ he didn't know much English, he got out his dictionary and looked up th

________ he didn't know much English, he got out his dictionary and looked up the word “cough”.
A. Since
B. So
C. As
D. Why

Answer 1

答案C
解析：“他不懂得很多英语”是he got out his dictionary and looked up the word “cough” 的原因，故前一个分句是个原因状语从句。选项中的so和as都可以表示原因，但since起说明的作用，因此C为正确答案。
注意：so可以用作并列连词；why不能引导状语从句。