1、They are intangible, immaterial and would be undetectable if the passengers stopped moving.
他們是無(wú)形的，非物質(zhì)的，而且即使旅客都停下來(lái)也無(wú)法察覺(jué)。

2、Look, it says here that the noise from it should be undetectable by other people.
看，這里說(shuō)的是它發(fā)出的聲音應(yīng)該不會(huì)被其他人察覺(jué)。

3、All welds shall be undetectable in finished work.
完成設(shè)備的所有焊接應(yīng)無(wú)法探察。

4、The sound is virtually undetectable to the human ear.
這聲音實(shí)際上是人耳難以聽(tīng)得到的。

5、These fractures may be undetectable on routine images from the radiographer.
這種骨折在一般的放射照像的圖片中很可能不會(huì)被發(fā)現(xiàn)。

6、Almost undetectable with even the most delicate instruments.
即使最精密的儀器都幾乎無(wú)法察覺(jué)的。

7、Polar Bears are nearly undetectable by infrared cameras, due to their transparent fur.
紅外線攝像機(jī)幾乎探測(cè)不到北極熊，因?yàn)?/a>它們的毛是透明的。

8、It is undetectable by metal screening devices.
它是金屬探測(cè)器無(wú)法探測(cè)到的。

9、The Windows are very clean and have undetectable levels of trace elements.
窗體很干凈痕跡元素水平低到無(wú)法覺(jué)察。

10、The 40 people with undetectable levels of nicotine and cotinine were classified as nonsmokers;
40位未檢出尼古丁和可替寧的志愿者被歸類為“非煙民”；