单选题What is the main idea of the second paragraph?A Dave got hurt during his journeyB Everyone can help others if he wishesC The environment of Australia is terribleD Dave challenged himself to achieve his dreams

正确答案：The Second Engineer is responsible for watching at periods of 0400-0800 hours and 1600-2000 hours; He is responsible to Chief Engineer for the operation and maintenance of all machinery and associated equipment; He is responsible for operational procedures of main and auxiliary engines according to their respective manuals; He is responsible for carrying out planned maintenance laid down by the Chief Engineer and keeping a full record of all work; He is responsible for all deck electrical, hydraulic and mechanical working conditional; He is responsible for well controlling over responsible for maneuvering the main engine; He is responsible for the cleanness of the Engine Room and associated compartments; He is responsible for assisting Chief Engineer in the preparation of spare parts and repair lists; He is responsible for familiarizing all pumping, piping, valve systems in the Engine Room together with all emergency equipment; He is responsible for taking care of the Engine Logbook, Engine Bell Book and other relevant record; He is responsible for participation in emergency drills; He is responsible for taking positive measures to prevent collision in co-ordination with Chief Engineer; He is responsible for assuming Chief Engineer

正确答案：A

48．答案为A。根据第四段描述内容作出该项选择。

正确答案：D
在文章的第二段中，作者的两个反问句都是针对笑及笑时的表情的，其目的在于强调笑这种现象究竟是什么。所以本题的正确答案应当为D。

答案：C

解析：

正确答案：D

答案：C

解析：

参考答案：ABCD