37.The new type of suitcase car （行李车）designed by our engineers is very ingenious（精巧） and practical.

我方工程师设计的新款行李车非常精巧、实用。

38.This kind of bicycle can be folded in half and handy to carry around, especially useful during traveling and traffic jams.

这种自行车可以折迭，携带方便，在旅行中或交通堵塞时特别有用。

39.The maximum speed of this kind of variable-speed（变速） bicycle is 30 km per hour.

这种变速车每小时的最大速度是30km

40.These machines have few breakdowns and are easy to maintain（维修，保养） because of their simple mechanical structure（机械结构）.

这些机器由于机械的构造简单，所以很少故障，易于保养。