题干
Advertising companies are always having to come up with new ways to ______ products.
A：desig
B：classify
C：promote
D：identify
答案(点此获取答案解析）
C
A：desig
B：classify
C：promote
D：identify
、—OH、
、—COOH四种基团两两组合而成的有机物中，其水溶液能使石蕊变红的有