下列化合物中既有离子键又有共价键的是()。
A.BaO
B.H2O
C.CO2
D.NaOH
参考答案:D
解析:非金属元素间以共价键结合,强非金属元素与强金属元素之间以离子键结合
小题1:“I am having a party for Lana,” he said. (改为间接引语)
He said he ____________ _____________ a party for Lana.
小题2:People here didn’t use money 300 years ago. (用in 300 years 改写句子)
People here ______________ ______________ money in 300 years.
小题3:They should buy some new clothes. (对画线部分提问)
______________ _____________ they buy?
小题4:Tom had a traffic accident yesterday. (同义句)
A traffic accident ____________ ______________ Tom yesterday.
小题5:你应该按时把书还给图书馆。
You should ____________ the book _____________ the library on time.
下列操作是设置某首音乐在多张幻灯片中播放的操作有()
A.“插入-音频-PC上的音频”的方法插入音乐文件
B.点击“动画-自动画空格”,在右侧的“动画窗格”下找到音乐名称(提示:音乐名称前有一个倒三角号),双击
C.在“效果”选项中点击“在张幻灯片后”,然后把数值改为要欣赏的图片的总张数,再点“确定”