A：there was a chance
B：there being a chance
C：it being a chance
D：it was a chance
如果∠1和∠2互为补角，且∠1＞∠2，那∠2的余角为（ ）
我国的根本政治制度是( )
____的掌声
____地鞠了一躬
____的故事
____地站了起来
