_______ you can sleep well, you will lose the ability to focus, plan and stay motivated after one or two nights.( )
Once
Unless
If
When
______ the instructions very carefully when filling in the form.
The school had promised to keep parents fully _____ about the conditions of their children at school.
I send you my revised catalogue and price list, ______ you may find something that suits you.
When he came back, he found his bag over the seat.
—How did he break his head while swimming? — my warnings, he dived straight into the shallow water.