______ quickly, _______ you won’t be able to catch the train.
Nowadays people sometimes separate their waste to make it easier for it ______.
At the age of 29, Dave was a worker, ______ in a small apartment near Boston and ______ what to do about his future.
When he ______ the door, he found his keys were nowhere.
In April, 2009, President Hu inspected the warships in Qingdao,____the 60th anniversary of the founding of the PLA Navy.
___not to miss the flight at 15:20, the manager set out for the airport in a hurry.