The international agreement, __________to help people kick off the habit of smoking, was signed two years ago.
His parents thought only in this way ________ become successful,studying abroad.
Hearing the bell ringing,out ________.
—When can I use your computer? —Never!________ should you touch it.
I really don’t know ________ I put my wallet after I paid the bill.
Behind the coach ________ our team wearing blue suits.