题目

Plan on traveling around the USA this summer．If you need help in arranging the trip，or want ideas about where to go and what to do, there are a number of outstanding websites that can make your American dream come true． http：／／byways．org The National Scenic Byways Program covers 150 memorable roads．Some are natural routes，such as Route l along the California coast．Others focus on history(such as Route 6) or man-made attractions (the Las Vegas Strip)．For each, you are provided with a map，told the route’s length and how long is allowed，and given detailed sugges在下列过程中，势能转化为动能的是A.踢出去的足球在草坪上越滚越慢B.一个小石块在竖直上抛的过程中C.上紧的发条带动指针转动D.一重物沿斜面匀速下滑