You heard wrong, it's not bullfrog, it's "bull!" It means you're awesome, top notch, excellent.

Bullfrogs are for eating, they taste delicious, not for describing people, here is a stir-fried bullfrog.

Depending on the specific type of question, step-by-step disassembly / cause principle analysis / content expansion, etc..

The specific steps are as follows:/ The main cause of this situation is ......