--- Why does the lake smell terrible?
--- Because large quantities of water _________.
A．have polluted B．is being polluted
C．has been polluted D．have been polluted
The disappointed father felt no way to live, ______ at the _____ son angrily.
A．staring; disappointing B．having stared; disappointing
C．stared; disappointed D．having stared; disappointed
After he became conscious, he remembered ______ and_____ on the head with a rod.
A．to attack; hit B．to be attacked; to be hit
C．attacking; hitting D．having been attacked; hit
______, we had to put off the tennis match.
A．It being rainy B．There being raining C．Having been raining D．Being rainy
_______ from other continents for millions of years, Australia has many plants and animals not found in any other country in the world.
A．Being separated B．Having separated
C．Having been separated D．To be separated
How ______ you did so much work with such a short time?
A．did it come about B．did it come about that
C．came about that D．was it that came about
