100. I ——speak a little English when I was four.
A. am able to B. was able C. could be able D. could
理由如下:
时间状语when I was four指示主句中的动词用过去形式;
这道题考察can和be able to同义;
选项A为现在时,与when I was four时态不匹配,故不可选;
选项B漏了to, was able to是正确形式;
选项C can与be able (to)叠用且漏了to,故不可选;
选项D can的过去时态could是可选形式;
所以,此题选 D。