空气中两列波长相同的简谐波发生干涉现象,若在某一时刻P点恰好是两列波的波峰相遇,Q点恰好是两列波的波谷相遇,则下列结论正确的是 ① P点的振幅最大,Q点的振幅最小 ② P、Q两点的振幅均是原两列波振幅之和 ③ P、Q两点的振动频率相同 ④ P、Q两点始终处于正向最大位移和负向最大位移处
________ many things change a lot, a love of sports hasn’t changed a bit.
If
Before
Though
Because
Mr. Smith created a new game. Soon all his students ________ rules to play it.
teach
taught
are taught
were taught
Don’t leave your toys on the table, or I ________ them away.
threw
will throw
have thrown
was throwing
—Who do you think will win the race, Bob or Tom?
—It must be Bob. I think he runs ________.
faster
fastest
more slowly
most slowly
________ me, I’ll show you the way.
Follow
Forget
Leave
Punish