There was never any time for Kate to feel lonely, _____ she was an only child.[ ]

How beautifully she sings! I have never heard _______ voice.

I admire my English teacher I can remember very few occasions ________ she stopped working because of ill health

This series of products ______ in special price for a month to promote its sales from next month

He’s still not understood by his close friend although he has said sorry to him； ______