Mom my friends Dave and Jack.A. this isB. they isC. he and sheD. these are

问题补充：

Mom, my friends, Dave and Jack.

A. this is

B. they is

C. he and she

D. these are

答案：

A. this is

B. they is

C. he and she

(答案→)D. these are

解析：Dave and Jack是两个人，要用复数，排除A;B中they后面要用are;C中没有动词；只有D.these are

是对的。故选D。