It was _____ back home after the experiment.
— I was so sure that our experiment was going to succeed, but something went wrong at the last moment.
— ______ , but don’t give it up.
“Must we start the experiment now?” “No, you ().”
It was ______ the chief engineer came ______ we began the experiment.
It was ______ the chief engineer came ______ we began the experiment.
You must explain()how they succeeded()the experiment.
_____
But for their generous help, the experiment ______ completed so quickly.
The original experiment cannot be exactly duplicated.
We must()that the experiment is controlled as rigidly as possible.