--- Have you heard that Jenny, along with her classmates,        to Harbin for the winter vacation?

--- Really? No wonder I haven’t seen her these days.

A．had gone

B．have been

C．has gone

D．have gone

课间操的作用不包括（）。

A.消除学习中产生的疲劳

B.提高学习效率

C.保护视力

D.防止脊柱畸形