下列说法错误的是（ ）
A．燃烧时一定伴有发光现象
B．燃烧一定要有氧气参加
C．燃烧一定是氧化还原反应
D．燃烧一定会放出热量
答案：B
What depressed her was that although she kept waving her hand, nobody seemed _______ her new watch.
A．noticing
B．to have been noticed
C．to have noticed
D．having noticed
从给出的选项中，选择最合适的一个填入问号处，使之呈现一定的规律性。（）
A．
B．
C．
D．
