Mary ________ as a secretary in this company for twenty years and now she stays at home taking care of her own garden.
After the disaster, the first thing the local government did was to provide _____ for the homeless families.
Most scientists seem to agree that ______ certain limit should be set on _______ consumption of cars to ease air pollution.
Helen devoted herself ________to her research and became a top scientist in the field of applied physics.
Vitamin D helps our bodies make a special chemical,and this special chemical, ______ affects our brains,making us feel happy.
Everyone must have known the death of the waitress, __________?