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【单选题】
科技馆中的一个展品如图所示,在较暗处有一个不断均匀滴水的水龙头,在一种特殊的间歇闪光灯的照射下,若调节间歇闪光间隔时间正好与水滴从A下落到B的时间相同,可以看到一种奇特的现象,水滴似乎不再下落,而是像固定在图中的A、B、C、D四个位置不动,对出现的这种现象描述正确的是(g=10m/s 2 )( )A.
水滴在下落过程中通过相邻两点之间的时间满足t AB BC CD
B.
闪光的间隔时间是s
C.
水滴在相邻两点间的平均速度满足 AB ∶ BC ∶ CD =1∶4∶9
D.
水滴在各点的速度之比满足v B ∶v C ∶v D =1∶3∶5
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【单选题】He knew the problem was serious and promised to look into it _____ he reached office.
A.
at that moment
B.
for that moment
C.
immediately
D.
soon
【简答题】When he left his parents he promised them that he would ______(尽量多写家信).
【单选题】Plato and Confucius believed that physical training was an important part of education.
A.
J
B.
K
C.
L
D.
M
E.
N
F.
O
G.
P
【简答题】（66-68题共用题干） 第66题：
【简答题】（68-69题共用题干） 第68题：
【简答题】（68-71题共用题干） 第68题：
【单选题】He knew the problem was serious and promised to look into it ____ he reached office. [ ]
A.
at that moment
B.
for that moment
C.
soon
D.
immediately
【单选题】He ____ to come today, but he didn't keep his ____. [ ]
A.
promise; promise
B.
promised; promised
C.
has promised; promise
D.
promised; promise
【简答题】（68-72题共用题干） 第68题：
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