______ he referred to in his article was unknown to the general reader.
We often talk a great deal about English language teaching, ______ that it is the learning that really matters.
Many companies give away small quantities of their produce as samples ______ people can try them before buying them.
In the rainforest of the Amazon, 50 to 150 plant species ______ every day.
— This is a good place for a picnic.— Yes, it couldn't be ____ .
He was very busy yesterday, otherwise he ____ to the meeting.