已知a是方程2x²+3x﹣6=0的一个根，则代数式3a（2a+1）﹣（2a+1）（2a﹣1）的值为____ 

根据中文意思完成句子。
____ 课间，你们最好去室外散散步。
__________go out for a walk during the break.
____ 在日常生活中，向雷锋学习对我们来说是有益的。
____________learn from Lei Feng in our daily life.
____ 我刚才看到他们正在操场上跑步。
I ____________________on the playground just now.
____ 玛丽检查得很仔细，在考试中她没犯任何错误。
Mary checked so carefully __________________________in the test.
____ 恐怕这场大雨将迫使他们把运动会推迟到下周。
I’m afraid that _______________________________.

— May I speak to Mrs. Black?

— Sorry, mum can't come to the phone now. She        a shower.