The most important thing is to keep _____ when you get into difficulties.

Not a single book is allowed _________ out of the reading room according to the new rule

Our manager ________ for Shanghai in a few daysand he has asked me to find out when the earliest plane ________ nextWednesday

The GPS, originally _______ by the US military, covers the whole world

We are looking forward to______another chance ______ it again.[ ]