A cough is usually nothing to worry about unless it lasts for ten days _____

Stress can be extremely damaging to your health. Exercise, __________, can reduce its effects.

--- I __________ agree with what he said. Actually I feel what he said is much to the point and makes good sense. --- Yes, I think so.

As is known to all language learners, the newly learnt words will soon be forgotten unless______ used in everyday communication.

To be honest, I tend to agree with Shirley, though not _______________.