Flu is a very ______ infectious disease. Fever, headaches, coughing and fatigue are some of its ______ symptoms.
In 2014, a series of important reform measures were introduced in China, many of which are so closely associated with the interests of the general public _______ almost each person could benefit from in life.
—Mum, where are my new socks?— How _______ I know? You’d better not put your things everywhere.
It is not ________ it is useful to study nature but he takes pleasure that the scientist study nature.
I used to go camping a lot, so it wasn’t the first time I ______ in a tent.
The song is sung all over the country, ______ it the most popular song this year.