It is thought that the new vaccine will be available by next year.
TO
The new vaccine .................... available by next year.
The experiment failed because the equipment was not accurate enough.
TOO
The equipment was .................... experiment to succeed.
I am sure the researchers have already published the results.
MUST
The researchers .................... the results.
'Have you finished analysing the data, Professor?' asked the student.
IF
The student asked the Professor .................... analysing the data.
Nobody has ever made such an important discovery in this field.
MOST
This is .................... ever made in this field.
The manager did not allow the staff members to leave early on Friday.
PERMITTED
The staff members .................... leave early on Friday.