A new theory ______ before it can be put into practice. A: must be tested B: be tested C: can be tested D: to be tested

By the date of delivery the products should be manufantured,tested, packed, marked and delivered under conditions stipulated by the present contract.其中划线短语的意思是：截止到.....日期为止。

This is the material ______ in the laboratory last week. A: to be tested B: B. testing C: being tested D: D. tested

You can’t use the machine because it __________________ (not test) yet. A: has not been tested B: was tested C: has tested

智慧职教: The reserve source of energy must be tested_____under GMDSS if the reserve source of energy is a motor generator,not a battery.

I had no idea of the machine _______ already. A: to test B: having been tested C: testing D: having tested

You can't use the machine because it ___ yet. A: has not tested B: has not been test C: has not been tested

. Which of the following is true'? A: . a compulsory VHF-DSC radiotelephone installation must be daily tested without radiation. B: a compulsory VHF-DSC radiotelephone installation must be annually tested without radiation C: a compulsory VHF-DSC radiotelephone installation must be monthly tested without radiation. D: a compulsory VHF-DSC radiotelephone installation must be weeklv tested without radiation.

Economic models are most often tested

The<br/>ideas were tested by experiments.