1. people , police , clothes 等词做主语时,通常用作复数;
2. have 是句子的谓语动词;more interest 宾语;in sports 介词结构,作定语;now 状语;
句子的意思是:现在人们对运动更感兴趣;
have more interest in ... = be more interested in ... = 对···更感兴趣。
have interest in 对····有兴趣,等同于 Be interested in ,所以该句谓语是一动词词组。
不一定,得看语境