题目

How old are the apps on your smartphone? Is it time for an update? Here are three apps for you. Try them out and have fun. Duolingo Learning a foreign language doesn’t always mean you have to sit in a class and take endless exams. An app called Duplingo has been designed to help you memorize(记住)new words and grammar in creative ways, such as online lessons, games and interesting exercises. For example, one exercise asks you to put words in the right order to make the correct sentence. You can also try translation practice. Douban FM A music app is a necessity for almost every sma---- It’s difficult for the village children to cross the river for school．---- I think a bridge ______ over the river．A．was built B．is being builtC．has been built D．should be built