3.Why is Rwanda setting up "drone ports"？

A. Because they are receptive to new technology.

B. Because there are too many drones.

C. Because they're easier to construct than roads.

D. Because road travel there is rough.

答案　D

解析　推理判断题。根据An Airport for Drones(无人机)中的"The goals are to make it easier to transport food，medical supplies，electronics，and other goods through the hilly countryside."可知，他们想用无人机在山区运送物资，由此可推知，在山区里，公路交通很艰难。故选D。

(2018•黑龙江哈三中高二期中)

A new study has discovered that meditation(冥想) and oxygen sport together reduce depression. The Rutgers University study found that this mind and body combination，done twice a week for only two months，reduced the symptoms for a group of students by 40 percent.

"We are excited by the findings because we have seen such a meaningful improvement in both clinically depressed and non-depressed students，" said lead author Dr Brandon Alderman."It is the first time that both of these two behavioral ways have been looked at together for dealing with depression."

Researchers believe the two activities have an interactive effect in combating depression. Alderman and Dr Tracey Shors discovered that a combination of mental and physical training(MAP) enabled students with major depressive disorder not to let problems or negative thoughts defeat them.

Rutgers researchers say those who participated in the study began with 30 minutes of focused attention meditation followed by 30 minutes of oxygen sport. They were told that if their thoughts drifted to the past or the future，they should refocus on their breathing，enabling those with depression to accept moment-to-moment changes in attention.

Shors，who studies the production of new brain cells in the hippocampus-part of the brain involved in memory and learning-says scientists have shown in animal models that oxygen sport exercise keeps a large number of certain cells alive.

The idea for the human intervention(干预) came from her laboratory studies，she says，with the main goal of helping individuals acquire new skills so that they can learn to recover from stressful life events.

By learning to focus their attention and exercise，people who are fighting depression can acquire new learning skills that can help them process information and reduce the overwhelming recollection of memories from the past，Shors says.

"We know these treatments can be practiced over a lifetime and that they will be effective in improving mental health，" said Alderman."The good news is that this intervention can be practiced by anyone at any time and at no cost."

语篇解读　本文是一篇说明文。本文主要介绍了一项研究成果--将冥想和有氧运动结合起来治疗抑郁有很明显的效果。