---Why hasn’t Jane arrived yet?  

---She ______ again in the morning.

A．shouldn’t have overslept

B．may have turned off the alarm clock

C．must have no one to call her

D．should have someone to wake her up

由创设情境、确定问题、自主学习三个步骤组成的教学策略是（）。

A.抛锚式教学策略

B.随机进入教学策略

C.支架式教学策略

D.启发式教学策略