问题
选择题
Mom, my friends, Dave and Jack.
A．this is
B．they is
C．he and she
D．these are
答案
答案：D
题目分析：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。
点评 ：如果后面只有一个人的话，即选A。Mom，this is my friend, Dave.