How often are the Olympic Games held – fouryears.

Here you are at last! What kept you so long—Sorry, I’m late. But do you know what greatdifficulty I have ______ your house.

I hear Peterson was badly injured in the accident.— , let’s go and see him.

下列各句中没有通假字的一项是（ ）

Sometimes our opinions differ _________ what we choose to observe and how we deal with what we’ve observed