Double or Compound into Simple Sentences

Double or compound into simple sentences:
1. Double sentence के finite verb को participal (verb+ing) में बदल दिया जता है; या
2. आवश्यकतानुसार उस जगह to, for, after, by, unless, owing to, in spite of आदि का प्रयोग किया जाता है।
Look at these sentences;
Double (compound)-
(a) He bought a book and read it.
Simple-
(a) After buying a book he read it.