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

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

3、All welds shall be undetectable in finished work.
完成設備的所有焊接應無法探察。

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

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法察覺的。

7、Polar Bears are nearly undetectable by infrared cameras, due to their transparent fur.
紅外線攝像機幾乎探測不到北極熊，因為它們的毛是透明的。

8、It is undetectable by metal screening devices.
它是金屬探測器無法探測到的。

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法覺察。

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”；