题干
—Who ________ they?
—They are my friends.
A：was
B：were
C：are
答案(点此获取答案解析）
C
—They are my friends.
A：was
B：were
C：are
Ca2+(aq)+2OH-(aq)，现向其中加入少量CaO粉末，则下列说法错误的是：
