A、 there
B、 here
C、 where
D、 now
答案:C
A、 there
B、 here
C、 where
D、 now
答案:C
A. check
B. explain
C. describe
D. mark
A. On
B. For
C. By
D. With
A. “章动”由月球离地球的位置变化而引起,是地轴的一种较短周期的“镜像摆动”。
B. “张德勒颤动”是地板的不规则运动,其轨迹并不是完美的圆,而是10码长的曲线。
C. “岁差”是太阳和月球对地球赤道部分的吸引造成的,是地轴的一种长周期运动。
D. “第四种颤动”与地球的大气、风暴及雪盖运动等有关,是地球外部因素造成的。
A. had begun
B. will begin
C. has begun
D. begins
A. sounds
B. feels
C. smells
D. looks
A. To have changed
B. Change
C. Changing
D. Being changed
A. bright
B. weak
C. soft
D. natural
A. to
B. at
C. for
D. with
A. hard
B. harder
C. hardest
D. hardly
A. had begun
B. will begin
C. has begun
D. begins