What is a 'test bed'?

[Lusen]

Test No. incompl/inter-59 "Testing, Testing", question 9

The aircraft engine had to be placed in a test ......... to make sure that it worked properly.

(a) pit
(b) hole
(c) bed
(d) centre

Test No. incompl/inter-59 "Testing, Testing", answer 9

The aircraft engine had to be placed in a test bed to make sure that it worked properly.

Correct answer: (c) bed

Your answer was: incorrect
The aircraft engine had to be placed in a test centre to make sure that it worked properly.
_________________________

Why do you use the word 'bed'?

[Alan]

This is the place where the aircraft is placed.
_________________
English as a Second Language
You can read my ESL story Present Simple