The following chapters provide step-by-step instructions for practical _______ of genetic (基因)engineering to agriculture.

We don’t have enough nurses to look after the patients. At least _____ are needed.

The village______I was born has changed a lot.

I _____have breakfast at 7:00. But ____ it’s 7:20. I’m having my breakfast.

We have sweaters____all colors_____ 50 each.[ ]