20. GWD-30-Q20:

Researchers have announced that the magnetic fields emitted by one manufacturer’s security surveillance system, of which type there are 200,000 worldwide, can interfere with pacemakers and that this interaction can bring on missed or irregular heartbeats, nausea, breathlessness, dizziness, and even fainting.

1. of which type there are 200,000 worldwide, can interfere with pacemakers and that
2. of which, worldwide, there are 200,000 of that type, and which can interfere with pacemakers, and
3. of which type there are 200,000 worldwide, they can interfere with pacemakers and
4. 200,000 of which type exist worldwide, interfering with pacemakers, and
5. 200,000 of that type existing worldwide and can interfere with pacemakers, and

   Answer:

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21: GWD-29-Q41

Gas hydrates, chemical compounds of water and natural gas, are increasingly being studied for their potential to be huge reservoirs of energy, possibly causing sea floor instability, and significant contributors to global warming.

1. to be huge reservoirs of energy, possibly causing sea floor instability, and
2. to be huge reservoirs of energy, possibly causing sea floor instability, and even as
3. as huge reservoirs of energy, possibly causing sea floor instability, and
4. as huge reservoirs of energy, and the possible cause of sea floor instability,
5. as huge reservoirs of energy, as possible causes of sea floor instability, and even as

1. more research was needed to determine that balloon angioplasty preceded with ultrasound was or was not any better for heart attack patients than
2. more research was needed for determining whether or not balloon angioplasty preceded by ultrasound is any better for heart attack patients than is
3. that more research was needed to determine whether balloon angioplasty preceded by ultrasound is any better for heart attack patients than
4. that more research was needed to determine that balloon angioplasty preceded with ultrasound was any better for heart attack patients than
5. that more research was needed for determining that balloon angioplasty preceded by ultrasound is or is not any better for heart attack patients than is

上面三个题目的答案依次为A、E、C对么？

我觉得对哦．．．

不会都错吧