He seems too tired today, and I wonder he got a good sleep last night.
If you _______ a mistake in reviewing the report, please bring it to my attention.
This is a very special flower and it can _______ a strong sweet perfume at night.
In the botanical garden we can find a(n) _______ of plants that range from tall trees to small flowers.
—You can’t finish the book in less than an hour, I suppose? —______.
Many manufacturers were accused of concentrating too heavily on cost reduction, often at the ______ of the quality of their products.