特种作业操作证到期未复审的，特种作业操作证（）。A、继续使用 B、失效 C、可以复审

世博会是展示人类文明成果的盛会，也是世界各国欢聚、沟通与合作的舞台。认识世博会是认识人类进步的捷径之一。“城市，让生活更美好”——2010年上海世博会主题，反映了当今世界各国对城市化进程中遇到的共同问题的关切，引领人们更多地去思考“什么是美好城市和美好生活”。上海世博会以“城市，让生活更美好”为主题表明[ ]

①意识活动具有自觉选择性

②社会意识具有相对独立性

③社会意识总是与时俱进的

④社会意识变化推动社会发展

A．①②

B．②④

C．①③

D．③④

阿伏加德罗常数约为6.02×10²³mol^-1，下列叙述中正确的是（　　）

A．1.4 g乙烯和丙烯的混合物中含碳原子数为0.15×6.02×10²³

B．16.2 g淀粉和纤维素混合物中共含碳原子数为0.1×6.02×10²³

C．1.5g C₂H₆中含有共价键的数目为7×3.01×10²²

D．标准状况下，2.24L CCl₄中含有的分子数为0.1×6.02×10²³

阅读下列短文：从每题所给的A、B、C、D四个选项中，选出最佳选项，将正确的选项涂在答题卡上。

A

Dear Alfred，

I want to tell you how important your help is to my life.

Growing up, I had people telling me I was too slow, though, with an IQ of 150 at 17, I’m anything but stupid. The fact was that I was found to have ADIID(注意力缺陷多动障碍). Anxious all the time, I was unable to keep focused for more than an hour at a time.

However, when something did interest me, I could become absorbed. In high school, I became curious about the computer, and built my first website. Moreover, I completed the senior course of Computer Basics, plus five relevant pre-college courses. 

While I was exploring my curiosity, my disease got worse. I wanted to go to college after high school, but couldn’t . So, I was killing my time at home until June 2012 when I discovered the online computer courses of your training center.

Since then, I have taken courses like Data Science and Advanced Mathematics. Currently, I’m learning your Probability course. I have hundreds of printer paper, covered in self-written notes from your video. This has given me a purpose.

Last year, I spent all my time looking for a job where, without dealing with the public , I could work alone, but still have a team to talk to. Luckily, I discovered the job—Data Analyst—this month and have been going full steam ahead. I want to prove that I can teach myself a respectful profession, without going to college, and be just as good as, if not better than, my competitors.

Thank you. You’ve given me hope that I can follow my heart. For the first time, I feel good about myself because I’m doing something, not because someone told me I was doing good. I feel whole.

This is why you’re saving my life.

Yours,

Tanis

Tanis wrote this letter in order to（）.

A.explain why she was interested in the computer

B.share the ideas she had for her profession

C.show how grateful she was to the center

D.describe the courses she had taken so far

粗面内质网不具备的功能是（）。

A.核蛋白体附着的支架

B.参与蛋白质合成

C.解毒作用

D.蛋白质的加工和运输

怎样鉴别松花粉的质量？