—Why did Mike ignore (不理睬) me completely when I said hello to him?—Oh, he was keeping ________ a problem.A．think about B．to think aboutC．to thinking about D
People are overweight for many reasons, the most important one of which is that they eat the wrong foods, get the wrong types of calories per meal, and they also eat meals at the wrong time each da
=
，且|
|=|
|，则这个四边形是（ ）
,由
。所以四边形是梯形。