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【简答题】
阅读理解。 Lots of people like diving into water, because they can explore the underwater world. But there is not her kind of diving. Some people dive into the sky! This is really a very exciting sport. A skydiver goes high up in the air on a plane. Then he jumps off the r)lane and floats in the air with the help of a parachute(降落伞). A parachute is like a huge umbrella. It is put on the back of the skydiver. When the skydiver reaches a certain height, he will pull a string and the parachute will open up in seconds and carry him gently down to the ground. Skydivers like doing a lot of fascinate tricks in the air. After jumping off the plane one after another, they will try to stay in the air and hold each other's hands. They can form different shapes. Is it safe to do skydiving?Yes, as long as we receive right training.But sometimes, accidents do happen. In Canada, two skydivers were killed in 1991 when they jumped off the plane. Because their parachutes got tied up with each other, the parachutes couldn't open up and both crashed down and died. 1. Why do people like diving into water? 2. How does a skydiver go up into the sky? 3. What does a parachute look like? 4. Where does a skydiver put his parachute? 5. Why were two skydivers killed in Canada? 6. What do you think of skydiving?
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举一反三
【单选题】细菌性病害的发生条件是( )
A.
高温低湿
B.
高温高湿
C.
高温干旱
D.
低温低湿
【判断题】不论社会角色是否变换,职业生涯的纵向发展,都要求从业者做到终身学习,不断提高职业素养。 ( )
A.
正确
B.
错误
【判断题】若点A位于H面内,则a与A重合,aˊ、a〞分别位于相应的投影轴上。
A.
正确
B.
错误
【单选题】如图所示,B点位于斜面底端M点的正上方,并与斜面顶端A点等高,且高度为h.在A、B两点分别以速度va和vb沿水平方向抛出两个小球a、b(可视为质点),若a球落到M点的同时,b球恰好落到斜面的中点N,不计空气阻力,重力加速度为g,则 则 ( )
A.
va = vb
B.
v a = v b
C.
a 、 b 两球同时抛出
D.
a 球比 b 球提前抛出的时间为
【单选题】六味地黄丸中用于滋补肾阴、泻肾浊的配伍药对是
A.
熟地黄配山茱萸
B.
山茱萸配泽泻
C.
山药配牡丹皮
D.
熟地黄配泽泻
E.
山药配茯苓
【单选题】利用植物的茎尖或叶片、茎段等,在无菌条件下,培养在玻璃器皿中人工配制的培养基上,使它发育成完整的植株,这种技术可以用来培育植物新品种,可以在较短的时间内大量繁殖植物,可以防止病毒的侵害。下列关于这种技术的叙述,正确的是 ①这种技术利用了植物细胞的全能性;②这种技术叫做组织培养,可以克隆生物体;③这种技术属于细胞工程的应用领域之一;④这种技术是一种无性繁殖的方式 [     ]
A.
B.
①②③
C.
①②③
D.
①②③④
【多选题】病害三角是指植物侵染性病害的发生是由( )三方面的因素相互配合决定的观点。
A.
病原物
B.
细菌
C.
环境条件
D.
光照
E.
寄主植物
【单选题】分规是用来等分线段和( )的工具
A.
给线段做记号
B.
量取线段长度
C.
找圆心
D.
绘制圆弧
【单选题】分规是用来量取和分割()的工具。
A.
直线
B.
C.
线段
D.
曲线
【单选题】一根绳子的两端分别固定在顶板和底板上,两固定点位于同一铅垂线,相距为 h 。一小球系于绳上某点处,以一定的速度在水平面内做匀速圆周运动,此时小球两边的绳均被拉直,两绳与铅垂线的夹角分别为 和 , 若下 面的 绳子中的张力为零,则小球的速度为
A.
B.
C.
;
D.
.
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