Hello, for English, I can refer you to some of the books for the CDS exam -

1. Wren & Martin’s High School English Grammar & Composition by S.Chand - It is good for basic grammar

 2. Word Power Made Easy by Norman Lewis - It is good for candidates with problems in the vocabulary section.

3. Objective General English by S. P. Bakshi - It is good for overall preparation for English section for CDS exam. Practice the exercises which will help you in understanding the topics. 

For general knowledge, you can refer the following books -

1. General Knowledge (Latest Edition) by Manohar Pandey (Arihant Publication) - Here you will find topics of Indian History, Geography, Indian Economy, Indian Polity, etc.

2. Read newspapers like the Hindu, Indian Express, and this will keep you updated with the current affairs section.

If you want to know more, click on the following link -

 https://competition.careers360.com/articles/best-books-for-cds-exam

All the best for your preparation!