题目内容：

阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

We always think it’s OK for us to leave our plants unattended during our vacation,but a recent study has led to a new 1.(discover).

Some scientists tested tobacco plants and tomato plants by cutting off their stems(茎)and 2.(stop)watering them.They then recorded their response with a microphone  3.(place)ten centimeters away.

They found that the plants began to scream ultrasonic(超声波)sounds, which they believed could convey their suffering 4. other plants.When the stem of a tomato plant was cut,the scientists found that 5. screamed 25 ultrasonic sounds of suffering within an hour.The tobacco plant that had its stem cut 6.(send)out 15.

The plants also seemed to respond to different 7.(stress)with the different intensities(强度)of sound.The scientists observed that the tobacco plants let out  8.(loud)sound when they were not watered than when they had their stems cut

The study answers the question 9.plants can feel pain or not.It can change the way that we think about the plant kingdom,which has been 10.(natural)considered to be almost silent.