He really succeeded and he___his success to his hard work.

I saw Mr Li at the meeting yesterday.— Did you? He ______ have attended, for he had asked for sick leave.

Mr Jenkins has been busy withhis work these days and seldom _________ to come over to have a chat with me

We must protect wild birds and animals because they are .

When __________ to danger and conflict, men tend to increase blood pressure, __________ nervous or anxious .