二氧化碳可以使澄清的石灰水变成______，还可以使燃着的小木条______。
变浑浊；熄灭
8. The doctor insisted she____in bed. But her smiling face suggested there____nothing serious.
A．stay; was
B．stayed; was
C．would stay; be
D．stay; be
Cisco 3550交换机设备只能工作在第二层。
