单选题 Scientists have attempted to determine what drives certain people to commit horrible acts, but ______ answers are difficult to find.

单选题 According to the media, China’s wind power capacity has ______ the previous level considerably.

单选题 The lawyer proclaimed that they couldn’t jump to conclusions because acceptable conclusions must be ______ supported by evidence.

单选题 Researchers conducted a set of psychological tests to determine the negative consequences of a sleep ______.

单选题 In addition to a sense of sight, bees also have an unusual sense of smell, so they can ______ more than 10 similar flower odors.

单选题 Some parents try to help solve the problems that their sons and daughters have in ______ to their college life.

单选题 Moving forward even in the face of great difficulties has become the most important ______ in my life and career.

单选题 To help the employees become more communicative, the company offered several workshops to those who were not ______ in social interactions.

单选题 The guest speaker decided to ______ his speech in order to leave enough time for his audience to ask questions.