The book was so interesting that he had read it for three hours ______ he realized it.( )
before
after
until
since
Mary shut the window just now ______ she could keep the insects out.
A.so thatB.whenC.tillD.after
This year's Beijing Music Awards will be covered ______ on Sunshine TV this Saturday.
A.livelyB.aliveC.livingD.live
—Mum,where is David?
—He ______ to see the science fiction film Back to the future.
A.is goingB.goesC.has goneD.was going
The Communist Party of China will have its 100th birthday ______ July 1,2021.
A.inB.onC.forD.at
Kitty sometimes eats ______ orange or some grapes after lunch.
A.anB.aC.theD./