It encourages the use of "good words and phrases" ( Hao Ci Hao Ju ), which are essential for scoring high in the Paper 1 Composition.
Doing the exercises ensures students can practically apply all the key words for each topic.
Here's a general, solid review of what you can typically expect from online sources that provide (likely for subjects like Chinese, Math, or Science — common in Singapore or China-based curricula):
