问题 选择题

在化肥和农药的施用过程中,下列操作正确的是

A.为了提高含氮量,可以不必考虑施用过程中化肥对土壤产生的不良影响

B.碳铵化肥可以和碱性草木灰混合使用

C.为增强作物的抗寒、抗旱能力,可以适当地施用一些磷肥

D.使用了某一效果显著的杀虫剂后,可以不必更换品牌长期使用

答案

答案:C

A错,化肥施用过多会破坏土壤的结构;B错,碳铵化肥不可以和碱性草木灰混合使用,会发生反应,失去肥效;C正确;D错,长期使用同一品牌,虫子会有抵抗能力;

选择题
单项选择题

Recently, I flew to Las Vegas to attend a meeting. As we were about to arrive, the pilot announced with apology that there would be a slight (16) before setting down. High desert winds had (17) the airport to close all but one runway. He said that we would be (18) the city for a few minutes waiting to (19) . We were also told to remain in our seats meanwhile with our seat belts fastened (20) there might be a few bumps(颠簸). Well, that few minutes turned into about four-five minutes, including a ride that would make a roller coaster(过山车) (21) by comparison. The movement was so fierce that several passengers felt (22) and had to use airsickness bags. As you might guess, that’ s not a good thing to have happen in a(n) (23) space because it only (24) to increase the discomfort of the situation.

About twenty minutes into the adventure, the entire airplane became very (25) There was now a sense of anxiety and fear that could be (26) noticed. Every passenger simply held on for dear life …except one. A (27) was having a good time! With each bump of the (28) , he would let out a giggle (咯咯地笑)of delight. As I observed this, I (29) that he didn’t know he was supposed to be afraid and worried about his (30) . He neither thought about the past nor about the future. Those are what we gown--ups have learned from (31) . He was (32) the ride because he had not yet been taught to fear it. Having understood this, I took a deep breath and (33) back into my seat, pretending I was (34) on a roller coaster. I smiled for the rest of the flight. I even (35) to giggle once or twice, much to the chagrin(随恼) of the man sitting next to me holding the airsickness bag.

25()

A.light

B.pale

C.easy

D.quick