题海网，海量题库；找题库、找试卷、找答案就上题海网。

已知为坐标原点，点 ， 过动点作直线的垂线，垂足为点 ， ， 记的轨迹为曲线 ．

下图示意世界年平均气温分布，读图完成下列要求。

 

These (香蕉)are for you.

“飘若浮云，矫若惊龙”是对下列哪位书法家的赞誉(　　)

农民起义通常是指由农民阶层发动的武装反对统治阶级的运动。我国历史上开此先河的是（    ）

已知长方体的体积为36，长为 ，宽为 ，则高为．

下列地理现象中，是由于地球公转产生的是（    ）

（题类A）抛物线y=ax²的焦点坐标为（0， ），则a=．

分针指向3，时针指向8和9之间，这时的时刻是（      ）。

一个数千位是6，个位是3，其余各位是0，这个数是．

下列是某位同学对阶段学习的有关内容的归纳：①物质的用途由它们的性质决定；②玻璃仪器加热前外壁一定要擦干；③工业上分离液态空气制得氧气和氮气是分解反应；④制取气体之前应先检查装置的气密性；⑤氧气的用途很多，比如可以做燃料；⑥分子和原子的本质区别是分子可分，原子不可分。该同学归纳正确的是（   ）

下列对传染病流行的基本环节的叙述正确的是（    ）

当收藏夹中收藏的网址较多时，我们可以用收藏家的管理功能加以整理。其中，不改变收藏夹内容的操作是（   ）

已知m≠0，直线ax+3my+2a=0在y轴上的截距为2，则直线的斜率为(   )

已知不等式4x-a≤0的正整数解是1，2，则a的取值范围是（  ）

“此日漫挥天下泪，有公足壮海军威。”海军名将邓世昌的英雄事迹是（  ）

2018年3月27日16时52分，枣庄泓劲商贸有限公司租赁枣庄甘霖实业有限公司的废旧厂房，在焊接施工过程中发生爆炸，造成6人死亡，4人受伤。一名AB型血的同胞因失血过多，需要输血，最好给他输的血型是(    )

听录音，选出相对应的答语（）

阅读理解

When my sister Martie told me she had put out tomato plants last summer, I was quite impressed.

She was a garden-beginner. Once they were planted, she tended to water them daily, anxiously awaiting the juicy tomatoes to appear. But, day after day, her plants were tomato-less while all of her neighbors who had also put out tomato plants were already enjoying the fruit of their labor.

Frustrated, Martie gave in and went to the market to search fresh tomatoes. While paying, Martie told the farmer her troubles. The farmer paused to think for a moment and then asked, "Well, what kind of tomatoes did you plant?"

"I think they were called Big Boy," Martie remembered.

"Well there's your problem," the farmer explained. "Big Boy and Better Boy tomatoes have a 95-day gestation (孕育) period whereas regular tomato plants produce fruit in as little as 70 days...you just have to wait a little longer for the Big Boys."

With that new knowledge, Martie went home with excitement, knowing they would be worth the wait.

Thinking about my sister's gardening experience, I had to smile. She just didn't know that Big Boy tomatoes took longer-neither did I-but once she discovered that information, she was no longer discouraged and upset about the lack of tomatoes on her plants. Instead, she was encouraged and excited to see them a few weeks later.

It makes me wonder how many of us have "Big Boy' dreams in our hearts, yet we just don't realize that they are of the "Big Boy" variety so we are discouraged and worn out with the waiting process. Instead of waiting with excitement, we give up on our dreams and figure we must have done something wrong to stop them from coming to pass. Frustrated, we see other people's dreams coming true, and we wonder why ours haven't yet been achieved.

在锐角三角形 中，角 ， ， 所对的边分别为 ， ， ，向量 与 平行.

（Ⅰ）求角 的大小；

（Ⅱ）求 的取值范围.