在硬土中使用混凝土桩，按锤质量与桩质量选择锤重，其比值为()。
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You can call 0207 484 8925 for more information about ______.
A. taxes and charges
B. tickets on other dates
C. specially designed group tours
D. travel agencies
The three workers from CityWatcher.com have ______.
A. volunteered to provide security camera equipment
B. offered to be monitored in the new security program
C. agreed to have silicon chips planted in their brain
D. had access to secure areas of their workplace
Many people are worried about the silicon chips because ______.
A. the new technology may introduce on people's privacy
B. they cannot get the implanted chips removed
C. the new laws about the technology might be abused
D. they are not assured of the effect of the chips
When scientists describe dolphins' communicative skills, their tone is rather ______.
A. affirmative
B. negative
C. playful
D. speculative
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