题目内容：

I’m a strong believer that learning different languages makes you look incredibly good when you’re in a foreign country and can understand and speak the language. The list below is 4 apps that will help you learn a foreign language! You can download them for free.

Babbel – Learn Languages

Babbel is an excellent language tool to help you progress step by step with learning a new language. It helps you learn grammar along the way as you work your way through the tasks and assignments. You need to pay a monthly subscription(定金), but this will still be cheaper than taking physical lessons with a tutor!

Duolingo: Learn Languages Free

The app has many languages to choose from and will work through the basics all the way to advanced words and sentences. It’s all completely free too! It’s incredibly well designed, looks great and will help you learn, remember and progress with just a little bit of time every day.

Tandem: Language Exchange

Rather than have you work through tasks and memorize different things, the app lets you match with people who share your interests but speak the language you want to learn. You can then have text, voice and video conversations with people who want to learn your native language, and in return you learn theirs, all by simply communicating with each other. It’s a great way to learn with only $1 a day.

Learn English – busuu

This app is perfect if you want to learn English. There are all sorts of audio and visual learning aids. You’ll find yourself working through interactive tests and learning tools for vocabulary and dialogue.

1.What is the purpose of the passage?

A. Sell apps to language learners.    B. Introduce language learning apps.

C. Teach language learners to use apps.    D. Teach languages through apps.

2.Which app suits best if you want to learn through communication?

A. Babbel – Learn Languages    B. Tandem: Language Exchange

C. Duolingo: Learn Languages Free    D. Learn English – busuu

3.What is Duolingo different from the other three apps?

A. It is completely free to use.    B. It is specially for English learning.

C. It is unsuitable for beginners.    D. It is the most effective（有效的）app.

4.What do the apps have in common?

A. They cover all languages.    B. They focus on grammar.

C. They contain many tests.    D. They are free to download.