For our middle school students, some courses are compulsory, while others are ________.
| A．flexible | B．optional | C．impressive | D．significant |
---- I am not able to solve some practical problems using Newton’s First Law of Motion.
----That’s just _______ most of the students are puzzled easily.
| A．what | B．why | C．how | D．where |
—What should we pay more attention to if we go out for a mountain camp.
—Nothing special. Take a special pair of glasses ______the wind there is strong and cold.
| A．now that | B．in case | C．providing that | D．so long as |
Some refugees made______ new life for themselves across the border, but they were troubled with homesickness in _____later life.
| A．a; 不填 | B．the; the | C．a; the | D．不填; 不填 |
— How did they _______ your suggestion?
— Opinions vary.
| A．reply | B．reacted to | C．object to | D．think |
The light above the elevator________ that the elevator was then at the fifteenth floor.
| A．indicated | B．suggested | C．symbolized | D．aimed |