As a _______ rule, most flowers appear in spring.

—What do you plan to do on the ___________ May Day holiday?—I have no idea. Probably, I will spend it by doing many papers.

 Would you please make up a topic ______ discussing at tomorrow’s conference?

Your ideas are very interesting, but we need _______ suggestions to get us out of the mess.

 With the weather getting colder, visitors from Australia spent their _____ days in 　　　　Beijing.