晶粒大小对钢材的磁性有何影响？
题型：问答题 简答题
问题：
晶粒大小对钢材的磁性有何影响？
题型：问答题 简答题
One of my favourite things to do is hiking in mountains. Because nobody likes the idea of getting lost, I always prepare before every trip. But what’s the best navigation tool, a Global Positioning System (GPS) or a good old map and compass? Five of my friends and I hiked through the mountains on a trail I marked. One team of three carried a GPS, and the other team used a map and compass.
It took the GPS team 3 hours and 11 minutes to get through the whole hike, however, it took the map and compass team only 2 hours and 49 minutes. The biggest problem the GPS team met was that they lost the satellite signal (卫星信号) in some places. With no map or compass, they had to walk around until they were in a place where the signal was good. The map and compass team was able to spot (认出) different landmarks, compare them to their maps and then use the compass to point them in the right direction.
When I head out on my future hikes, I’m bringing a map, a compass and a GPS to show me the way.
小题1:The writer prepares before every trip because he doesn’t _________.
A．like the old map or compass
B．know how to use the GPS
C．want to get lost in mountains
D．want to get into the mountains alone小题2:The two teams _________.
A．had the same navigation tool
B．went along the same trail
C．had the same problem
D．finished the whole hike at the same time小题3:In the end, the writer found out _________.
A．the map and the compass were too old navigation tools to use any more
B．it wasn’t necessary to bring a map and a compass together with a GPS
C．the GPS had some bad points in hiking in mountains
D．he wouldn’t use a GPS any more