若满足约束条件且向量，，则的取值范围是（ ）
Paper ____ first ____ about two thousand years ago in China by Cai Lun．（ ）
A．is； inventingB．is； invented
C．has； inventedD．was； invented
____ noise pollution， and we can live in a quiet environment．（ ）
Prevent
Preventing
Prevented
To prevent
Your new watch is so nice! When did you buy it？
In October． I ____ it for two months．（ ）
had
bought
have had
have bought
Linda has ____ to Paris． How can I get in touch with her？
Don't worry． She will call you as soon as she ____ there．（ ）
been；will get
been；gets
gone；will get
gone；gets
I like the TV program The Reader best． I think we should spend as much time as we can ____ in our spare time．（ ）
read
to read
reading
reads
满足约束条件
且向量
，
，则
的取值范围是（ ）
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