这是英语固定词组吗

help sb. do sth是指”帮助某人做某事“
help sb. doing sth没有这个用法
但是有can't help doing sth 这个说法 ”情不自禁做某事“
如I can't help falling in love with you.
我情不自禁地爱上了你

have fun doing sth.

help sb do sth.

help sb. to do sth.中to可省略不写

是help sb do sth 或help sb wuth sth