Explanation of key words:

1、pancake

As a noun, it is translated into pancakes, powder cakes and flat drops;

Fall flat, land flat, land flat, and spread flat.

2、challenge

Challenge, test, doubt, stop questioning and oppose;

The juror objected to someone's appearance in court.

Extended data:

The usage of challenge:

The basic meaning of challenge as a noun is to challenge and invite a game. Extension can refer to challenging things and arduous tasks. It can also refer to questioning the correctness or legality of something, and it can also refer to the stop order issued by the sentry, and stop questioning.

Challenge is often used with the preposition to bring out the object of challenge. Challenge can be followed by infinitive, which means to challenge someone or something.

Challenge is a transitive verb, followed by a noun, pronoun or clause as the object, and can also be followed by a verb infinitive as the compound object of complement, which can be used in passive structure.