试样制完后应存储在不吸水、不透气的密封容器中，并准确称量，以便测定在后续存储和运输中

将直线x＋y－1＝0绕点(1,0)沿逆时针方向旋转15°得到直线l，则直线l与圆(x＋3)²＋y²＝4的位置关系是(　　)

A．相交

B．相切

C．相离

D．相交或相切

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项.选项中有两项为多余选项。

__1__  Many things can become distractions (分散注意力). Your ability to focus your mind,

emotions and physical movements will directly influence your success. Staying focused on the

task at hand can be easier said than done. Here are some powerful techniques that can help you

improve your ability to focus.

For physical control, it helps to have a constant exercise schedule. __2__ Exercising helps you

gain better command of your body, and even goes beyond the body, giving you more flexibility

not just physically but also emotionally and mentally.  When you feel more comfortable in your

body, you increase your selfconfidence, which helps you feel more relaxed.

For mental control, meditation (沉思；冥想) does the task. __3__  It's easy to get distracted

by things in your background, but in order to perform well you have to maintain a high degree

of focus. When you relax your thoughts it trains your mind to deal effectively with outside

distractions so you can stay centered on what matters most at the moment.

__4__ It prevents you from overreaction and also from overacting. When your emotions settle

down, you gain greater awareness of the environment you're in, and feel calm and in control.

__5__ The good thing is that selfcontrol can be developed.  Start exercising frequently, get

yourself into meditation, and start to feel positive changes in your career and your life in general.

A. In short, focus requires selfcontrol.

B. There are many benefits of exercising.

C. Generally speaking, you need to practise a lot.

D. There are still some disadvantages of exercises.

E. Your emotions are well served by meditation as well.

F. Focus is an important part of success and achievement in general.

G. It helps block out all the noise and activities that are going on around you.

主动脉夹层造成内膜撕裂的主要因素有（）

A.主动脉中层囊性坏死

B.主动脉中层肌肉退行性变

C.血压的高度

D.血胆固醇含量

E.主动脉内膜斑块不稳定性

广东引领改革发展的大潮，实现了历史性的飞跃，属于文化建设范畴的思想理论研究与创新也很突出，尤其是关于解放思想方面的理论创新更是众所周知，包括（）。

A.社会责任研究

B.粤港澳合作研究

C.经济特区理论研究

D.改革开放理论研究

以下（）不属于信息系统学科的特点

A、综合性

B、交叉性

C、创新性

D、艺术性