根据意思写成语。
恍惚之中听见一声声音大得惊人的咆哮。 ____
She has ____( get ) five story books.
Security devices at airports are ______ to spot weapons that could be used by terrorists.
如图,在正方体ABCD﹣A1B1C1D1中,
(1)求证:AD1⊥平面CDA1B1;
(2)求直线AD1与直线BD所成的角.