Putting an index finger up to the lips is a popular way _____ Be _英语解答

Putting an index finger up to the lips is a popular way _____ Be quiet
to say
for saying
of saying
of say

人气：144 ℃　时间：2020-04-17 13:40:59

解答

of saying
以下供参考：
American ways of living
美国人的生活方式