The Australian boy has a good ________ of Chinese and can express himself freely in it.
A．power B．command
C．demand D．usage
—How can I use the equipment?
—Well, just refer to the ________.
A．directions B．explanations
C．expressions D．introductions
—Do you know why Jane was so angry?
—Her roommate gave in to ________ and opened the letter addressed to her.
A．curiosity B．consideration
C．concern D．convenience
In my brother's absence, I would like to thank all concerned on his ________.
A．behalf B．part C．business D．interest
—What does PM 2.5 mean?
—It's a professional ________ indicating the condition of air pollution.
A．term B．item C．number D．mark
It is no ________ pretending you did not know because everyone saw the whole accident.
A．use B．help C．time D．joke
