On foggy days, you have to drive very ________ on the expressway to avoid traffic accidents.

—— How did you find your visit to the museum? —— I thoroughly enjoyed it. It was＿＿＿＿interesting than I had expected. 

Nowadays the roles of husband and wife are not as ______ defined as before, especially when both parents work and earn money for the family.

 ---I was riding along the street and all of a sudden, a car cut in and knocked me down. ---You can never be         careful in the street.

The national parks are very important for the protection of these wild animals, which would ______ run the risk of becoming extinct.