$1,$ His father would rather to ask his son fix the broke radio
Cấu trúc: S + would rather + to - V
$2,$ It is not easy to do metal work
Cấu trúc: It's + (not) + adj + to-V
$3.$ His sister explained to her how to make cookies
Cấu trúc (phần đằng sau): How + to-V