6.The plate glass must be capable of ____ very high temperat

6.The plate glass must be capable of ____ very high temperature .
A sustaining B maintaining C retaining D obtaining
7.In the 18th century you had to keep on sharpening the point of your feather pen and _____ it in a jar of ink when you are writing .
A dripping B slipping C tapping D dipping
8.They tried to _____ him from drinking too much .
A limit B restrain C guarantee D restrict
9.It was not until one hundred thousand years after the big bang that photons were ____ from matter.
A set apart B set off C set free D set out