- Where your pen pal from? The United States. A. doesB. doC. isD. are

问题补充：

--- Where your pen pal from? --- The United States.

A. does

B. do

C. is

D. are

答案：

A. does

B. do

(答案→)C. is

D. are

解析：考察短语。句意:你的笔友来自哪里？——美国。结合语境可知前文缺少谓语动词，助动词do需搭配实意动词使用，短语be from表示来自哪里，本句中your pen pal为单数第三人称，故系动词用is，选C。