Today there are more airplanes ______ more people than ever before in the skies.
Not having promoted the new digital camera successfully, the company should its original marketing methods.
It is important to have your eyes examined regularly to check for any sign of eye disease that may not have any __________.
It was really ________ of your brother not to play the guitar while you were preparing your lessons.
Modern science has given clear evidence ______ smoking can lead to many diseases.
The new couple couldn’t afford a new house. _______, they bought a second-hand one.