题目

It is important to learn business English if you are going to successfully communicate with others. If a university offers a course on business English, it will be a good idea to take the class. Reading, writing and speaking English is necessary to start a business. Vocabulary and grammar are a good place to start learning business English. You need to know what words mean. Later, try to pronounce the words and use them in a sentence and ask someone who is good at English to help you.In business you will have to learn such things as taking messages, answering the phones with proper words and c如图，△ABC和△A1B1C1是以点O为位似中心的位似三角形，若C1为OC的中点，AB=4，则A1B1的长为（　　） A、1B、2C、4D、8