Which of the following suffixes can be used to form both nouns a

Which of the following suffixes can be used to form both nouns and adjectives? （ ）
A、-ion
B、-ism
C、-ity
D、-ist
【正确答案】：D
【题目解析】：本题考查后缀的使用。-ist既能作为名词后缀，又能作为形容词后缀，比如：communist n/a 共产主义者（的）。而-ion；-ism；-ity都只是名词后缀。