"Long tube" in Engpsh is "long tube." It comes from the Engpsh words "long" and "tube," which together describe a tube that is longer in length than a typical tube.
Example sentences:
"The long tube in the laboratory is used for experiments on gases."
(实验室里的长管用于气体实验。)
"The long tube of the telescope allows for better viewing of distant objects."
(望远镜的长管使远距离物体更容易观察。)