While _________the topic of music in class, all the students show great interest in it.
________I’m concerned, we are going to take an exam in a month.
--Thank you for your help.-- _________.
He put forward a good idea ________ gave us hope.
Rather than ____on a crowded bus, he always prefers _____a bike.
All of the students were_______ by the ________ speech given by the headmaster.