In order to prepare for the lesson on 4B, you have two sets of homework to do:

1) Grammar Bank 4B on modal verbs for speculation and deduction, plus adjectives and adverbs for speculation

2) Vocabulary Bank on sounds and the human voice student's book page 163

This morning (Tuesday 2nd November) the lesson was on 4A so you need to make sure you do the grammar bank on inversion if you missed the lesson.

I'm always assuming now that you have your own book with the key to check your own answers on any of these exercises from the student's book.