题目

 E Devon, 17, is used to paying her own cell phone and car expenses. But lately it's been harder. The family she baby-sits for hasn’t been calling as much as usual and she couldn't find a job over the summer. Devon's dad said it's a sign of the tough economy. He told her he's feeling the pinch too and that he had to use her college fund to pay the loan(货款).      This kind of money troubles isn't strange to common families these days. In fact, it's hard to avoid news about the economy on the screen of the TV or the computers recently. It can seem a bit worry and some families are hit3．机械运动是自然界最普遍的一种运动，下列不属于机械运动的是（　　）A．行星转动B．菊花怒放C．火箭升空D．信鸽飞翔