门窗固定中除混凝土外，均可使用射钉固定门窗框。
参考答案：错
解析：门窗固定中除混凝土外，禁止使用射钉固定门窗框。
She________the opportunity，but unfortunately she just let it go.
A．should have taken
B．must have taken
C．needn't have taken
D．can't have taken
（），我国政府签署《联合国 * * 败公约》。
