题干
It was late. She opened the door ________ because she didn't want to wake up her grandma.
A：angrily
B：quietly
C：loudly
D：heavily
答案(点此获取答案解析）
B
It was late. She opened the door ________ because she didn't want to wake up her grandma.
A：angrily
B：quietly
C：loudly
D：heavily
，则集合
中的元素个数为（ ）