单选题
We can all name slang expressions that have gone out of date, for instance, "right on" and "groovy" were popular in our parents" generation.
【正确答案】
A
【答案解析】解析：题干中的“We can all name slang expressions that have gone out of date”和“for instance，‘right on’and‘groovy’were popular in our parents’generation”是两个独立的句子，但是中间却用逗号连接，因此A项“逗号拼凑句”正确。