_______ human beings use it in a wrong way, like we did with nuclear technology, the advancement of science and technology has never led to decline of human development.
20.Helen devoted herself__________to her research and became a top scientist in the field of applied physics.
19.Vitamin D helps our bodies make a special chemical, and this special chemical,________,affects our brains, making us feel happy.
18.Everyone must have known the death of the waitress, __________?
17.---Tony is such a selfish person. ---I agree. Never again________with him.
16.After driving for 20 miles, Jackson realized that he______in the wrong direction.