The students are ___ young people between the age of sixteen and twenty.

Travelling west, you set your clock ______; travelling east, you set it ahead.

They’re ______ choosing a cautious policy in order to avoid a risk in such an important event.

The boy was＿＿＿＿＿＿eager to get a geography book. 

. --- Believe it or not, I passed the driving test at the first attempt yesterday.--- Great! But remember you can never be ___ careful when driving a car in the street.