Read each of the following short paragraphs and complete the phrase or sentence that expresses the main idea of the paragraph. The first letter of the missing word is given be fore the blank.1. Training a dog to be a watchdog often produces unexpected results. Some dogs quickly learn the difference between unwanted people and friends. This is because their masters welcome friends and invite them into their houses. However, some dogs will always attack the postman who comes to deliver letters.Dogs are expected to be d______when trained.
【正确答案】：different
【题目解析】：P32
