问题补充：
It is known to us that lions and tigers the cat family.
A. are belonging to
B. belonged to
C. belong to
D. are belonged to
答案：
A. are belonging to
B. belonged to
(答案→)C. belong to
D. are belonged to
解析：考查动词用法。belong to属于；这个词组没有进行时也没有被动语态。老虎和狮子属于猫科这是客观真理，用现在时。
