数学题：一个三角形被一个长方形挡住了，如图。它是（　）

A.直角三角形

B.锐角三角形

C.钝角三角形

D.三种三角形都有可能

数学题解答：答案为D。三种三角形都有可能。因为已经露出了一个锐角，但是不管是直角三角形、锐角三角形、钝角三角形都至少有两个锐角，所以无法判断它是哪种三角形。

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