单选题 My parents always eat healthy food. ______, they become more concerned about their health as they grow older.

单选题 To promote the full development of the country, it is ______ for China to become self-reliant in science and technology.

单选题 In order to keep drivers safe, mechanics are urged to make sure that car engines are properly ______ up.

单选题 My doctor told me she had never seen another patient _______ to that particular medicine.

单选题 No one wants to hear negative comments, but we need to learn to use _______ as a tool for improvement.

单选题 There are many different stories about the ________ in the proper use of English.

单选题 One of the chief ______ of education is to equip students with career skills.

单选题 Searching through emails for a particular piece of information is something very _________.