答案与解析：A　考查推理判断。根据第四段第五、六、七句"I managed to reach the podium (讲台) without falling down. I faced my classmates. My voice trembled a little, but mostly it was clear and strong"可知，"我"设法到达讲台而不至于跌倒，面对着同学们，"我"的声音有点颤抖。据此可以推断，演讲开始时"我"感到害怕。A项意为"害怕，恐惧"，故A项正确。

　　4．What did the speech bring to the author at last?

　　A．She had nothing to fear in life.

　　B．She got rid of her sense of shyness.

　　C．She won enough college credits.

　　D．She desired to become a speaker.

　　答案与解析：B　考查细节理解。根据最后一段第一句"Although I didn't realize it at the time, the successful completion of that speech gave me the confidence to participate in class at college, to give verbal reports, and to eventually break free from my shyness"可知，高中毕业典礼上演讲的成功完成给了"我"最终摆脱羞怯的信心，故B项正确。

　　B

　　[2019·陕西省摸底检测]Scientists are preparing to launch the world's first machine to clean up the planet's largest mass of ocean plastic.

　　The experts believe the machine should be able to collect half of the detritus in the patch - about 40,000 metric tons - within five years. In the past few weeks they have been busy welding together giant tubes that will sit on the surface of the sea and form the skeleton of the machine, creating the largest floating barrier ever made.

　　The system, originally dreamt up by Mr. Slat, will be shipped out this summer to the Great Pacific Garbage Patch, between Hawaii and California, which contains estimated 1.8 trillion pieces of plastic. It will be the first ever attempt to tackle the patch since it was discovered in 1997.

Mr. Slat was 16 and still at school when he was diving in Greece and first saw for himself the amount of plastic polluting the sea. "There were more bags than fish down there，" he recalls. Two years later he came up with a solution, quit university after six months and set up The Ocean Cleanup as a company. Mr. Slat says the first plastic to arrive on shore will be a major milestone. "We as humanity created this problem, so I think it's also our responsibility to help solve it，" he says.