我国游泳选手孙杨成绩之所以突飞猛进，军功章上有韩国选手朴泰桓的一半。正是朴泰桓与他水中争雄，堪称一时瑜亮，孙杨前进的动力才会如此足。这样的例子在体坛数不胜数：梅西和C罗、费德勒与纳达尔、林丹和李宗伟……这说明 （）
A：竞争的结果是优胜劣汰
B：良好的合作能够创造竞争中的双赢
C：竞争促进合作，合作促进竞争
D：竞争能培养对手的进取心并激发其潜能
计算x3•x2 的结果是（ ）
蛙捕获昆虫主要依靠（ ）
根据Jack的日程表，完成选择填空。
Mon
4:00-5:00pm
swimming class
Tue
7:00-9:00pm
meet Sam at his house
Wed
10:00-12:00am
Thu
10:00am
go to the airport to meet Mike
Fri
12:00-5:00pm
part-time job
Sat
10:00-10:30am
visit Uncle David at People's Hospital
birthday party for Tom
Sun
12:00-6:00pm
根据句意，用括号内所给单词的适当形式填空(1)A glass is used for ____ (drink) water.(2)What is the most ____ (use) invention in the world?(3)Do you know the ____ (heat) ice cream scoop?(4)This kind of bicycle was____ (invent) by a middle school student.(5)What do you think of these ____ (invent)?
