Ⅰ.单句语法填空
1．Tom was about to close the window ________ his attention was caught by a bird.
2．The manager put up a notice to keep the staff ________ (inform)of what to do this week.
3．I had just walked out of the kitchen ________ I heard someone crying for help.
4．He rushed out to see what ________ (happen)when he heard someone was crying for help.
