题目内容：

阅读下面材料，在空白处填入适当的内容（不多于3个单词）或括号内单词的正确形式。

On Thursday Mrs. Clarke locked the door and went to the women’s club as usual.

When she came home she sensed 1. unusual. Had someone got in? The back door and the windows were all locked and there was 2. sign of force entry. Had anything been taken? She went from room to room checking and 3. (find) her spare camera missing.

The following Thursday she went out at her usual time, but she just took a short walk in a park nearby, came home through the back door and settled down to wait and see what 4. (happen).

It was 4 o’clock 5.  the front doorbell rang. Mrs. Clark was making tea at the time. The bell rang again, and then she heard her letter-box 6. (push) open. Picking up the kettle of boiling water, she moved quietly towards the door. A piece of 7.  appeared through the letter-box, and then a hand. 8. wire turned and caught around the knob (圆钮) on the door-lock. Mrs. Clarke raised the kettle and poured the water  9. the hand. A sharp cry was heard outside as the wire fell to the floor and the hand was 10.  (instant) pulled back, which was followed by the sound of running feet。