In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
Scientists (1) ______ Oxford University say their experimental coronavirus vaccine (2) ______ been shown in an early trial to prompt a protective immune response in hundreds of people who got the shot. British researchers first began testing the vaccine in April in about 1,000 people, half of (3) ______ got the experimental vaccine. Such early trials are usually designed only to (4) ______ safety, but in this case, experts were also looking to see what kind of immune response was (5) ______ .
Select the most appropriate option to fill in blank number 3.
In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
Scientists (1) ______ Oxford University say their experimental coronavirus vaccine (2) ______ been shown in an early trial to prompt a protective immune response in hundreds of people who got the shot. British researchers first began testing the vaccine in April in about 1,000 people, half of (3) ______ got the experimental vaccine. Such early trials are usually designed only to (4) ______ safety, but in this case, experts were also looking to see what kind of immune response was (5) ______ .
Select the most appropriate option to fill in blank number 3.