people must promise to take care of their new tet---must people promise to------这个地方知道填什么吗

people must promise to take care of their new tet---must people promise to------这个地方知道填什么吗
people must promise to take care of their new tet
---must people promise to---
---这个地方知道填什么吗

people must promise to take care of their new tet---must people promise to------这个地方知道填什么吗
what--- do

What must people promise to do?

must people promise to take care of their new tet?
一般疑问句的提问,将动词提前就好了,其他部分位置不变