按照创新活动的来源不同,可以将创新活动分为()。
A.跨越创新
B.引进消化吸收再创新
C.原始创新
D.集成创新
参考答案:B, C, D
—Look, those great notebooks are __________in our school store. Let’s have a look.
—OK. Anybody can __________ the prices.
A.sell, buy
B.sell, afford
C.on sale, afford
D.on sale, sell
区间无源应答器主要提供固定的线路信息,如轨道区段、线路坡度、线路速度等