When ______ comes to research into heart disease and its effects on the body, we do not have adequate substitutes for the use of animals.
He was in the mountain for a year. He felt as if he was ________ from the outside world.
The speaker is giving rather an________ speech, as I can judge from the________ look of all the listeners.
He walked down the hills, and ________ softly to himself.
The sun was shining brightly, ________ everything there ________ more beautiful.
Most Year 3 students in Quzhou No.1 High School are working hard day and night for the 2014 college entrance examinations, hoping to gain __________ to their dream universities.