阅读理解
Mobile technology has created new ways for all types of learning styles to help discover new information. If you want to teach yourself things, here are some apps that will help you.
Coursera
Perhaps one of the biggest advancements in the history of e-learning, Coursera has teamed up with top school like Duke, Stanford, and John Hopkins to bring you direct access to real college courses in psychology, computer science, business, and technology. Each course features pre-recorded videos, projects, and quizzes, just like you'd receive inside the classroom.
Lumosity
This app features three-day sessions that target many different areas of brain activity: memory, speed, problem solving, and thinking flexibility. Each day you can participate in a timed session to sharpen mental intelligence and keep track of your progress over time.
Duolingo
If you've ever wanted to learn a new language but didn't know where to start or couldn't afford expensive apps, you need to check out Duolingo. This app teaches more than a dozen languages by breaking up exercises into mini games. The developer of Duolingo claims that 34 hours of learning in this app equals a full term's worth of school.
EarthViewer
Ever wonder what Earth looked like a million years ago? There's no better way to know than to look for yourself. Earth Viewer takes you on a digital journey to see how the landscape(地貌) and face of the planet has developed over the past 4.5 billion years, and view climate changes, sea level adjustments, or the evolution of famous cities.
，就是把这个数（ ）。