1_____education is the instruction that occurs when the instructor and students are separated by distance or time,or both

Which do you think is ________, health or wealth？

维生素按溶解性分为（）类和脂溶性类两大类，后者如维生素A、D、E、K。

（）包括水溶性和脂溶性两种。

Either he or I ______to the airport.

Duty is an act or a course of action that people __________you to take by social customs, law or religion.

Duty is an act or a course of action that people ______you to take by social customs, law or religion.

Project ______is an uncertain event or condition that，if it occurs，has a positive or a negative effect on at least one project objective，such as time，cost，scope，or quality．

It will be a relief over the death of a friend or a relative if the friend or relative dies from ______.

Hurry up, or you ______ catch the train.

食用油脂是人体热能、（）和脂溶性维生素的重要来源。

表面活性剂能增加难溶性药物的溶解度是因为________。