Below the threshold dose level, no adverse events above the response at the control level which is called the background response occur, then background response also occurs at the threshold level.

当剂量水平低于这个门阀剂量水平时，该剂量水平下的反应要比控制剂量下的反应即背景反应低，并且本文假定该门阀剂量水平下的反应与背景反应相同。

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14：The lunar rover for Apollo 17, called the LRV-3, sits in its finalparking spot on the Mare Serenitatis, the Lunar Module in the background onDecember 13, 1972.

该月球车称为“LRV-3”，停在澄海(Mare Serenitatis)最后一个停放地点，背景显示的是阿波罗17号登月舱。

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Due to the omnipresence of dioxins, all people have background exposure and a certain level of dioxins in the body, leading to the so-called body burden.

由于二恶英普遍存在，因而所有人都有接触的环境且身体里都有一定程度的二恶英，也就产生了所谓的机体负担。

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Incredibly, last November the Federal Bureau of Investigation says there were about two million background checks called into The National Instant Criminal Background Check System (NICS).

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"We've got to work hard and the more people know about the bill, the more people read the bill, the more people see the facts of the bill, it breaks down all the misnomers, " he said of what he called misinformation about the background check proposal being spread by opponents.

CNN: Senate gun law proposal lacks enough support now

These are the so-called loopholes in the current federal background check system.

CNN: 'Universal background check:' What does it mean?