请用括号单词的恰当形式填空(loud)<br>The students began to enter the classroom and Anna was startled at their___

请用括号单词的恰当形式填空(loud)
The students began to enter the classroom and Anna was startled at their____.

请用括号单词的恰当形式填空(loud)
The students began to enter the classroom and Anna was startled at their____.
【正确答案】：loudness

企源知识库