Question: Maple doesn't responde

Hello, I'm using free 15 day trial Maple 2019.2 on my Macbook (Macos 10.15.3).

I can't work Maple. I enter some inputs (2+3) and press enter. It works. But when I write plot, version(), f, sin.. or something else it didn't works. And no response. When I click enter, nothind happen. What is the problem? Please help me.. 

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