It can be expanded like this:

1, The ripe pods cracked open quietly.

2, When fall came, the full pods were bursting open.

3, The bunches of full pods were all cracked open like a child's mouth.

4. The soybeans in the field were ripe, and the pods split their mouths and smiled sweetly.

Expanded:

Methods of Sentence Expansion

1. Local Expansion Method.

That is, the sentence is divided into two parts - the subject part and the predicate part, first expand the front part, and then expand the back part.

such as "Xiaoming reading", the front part of the "Xiaoming", first add Xiaoming who, with my relationship, so that the front part of the expansion can be "my classmate Xiaoming"; The latter part of the sentence can be supplemented with "where" and "how to read", so that the latter part can be supplemented with "in the classroom to read carefully". The whole sentence can be expanded to "My classmate Xiaoming reads carefully in the classroom.

2, the overall expansion method.

It is to expand the two parts of the sentence at once. Such as "the red flag rose", according to "what kind of" red flag "in what place" "how to" rose up, can be expanded to "brightly colored five-star red flag on the roof of the teaching building slowly rose up".

Baidu Encyclopedia - Expanded Writings