用pH试纸测定某无色溶液的pH时，规范的操作是                           [ ]

A．将pH试纸放入溶液中观察其颜色变化，跟标准比色卡比较

B．将溶液倒在pH试纸上，跟标准比色卡比较

C．用干燥的洁净玻璃棒蘸取溶液，滴在pH试纸上，跟标准比色卡比较

D．在试管内放少量溶液，煮沸，把pH试纸放在管口，观察颜色，跟标准比色卡比较

Text refers to any piece of spoken or written language, which expresses a complete meaning. Which of the following are texts

A．DANGER!

B．The novel Pride and Prejudice.

C．The China Daily

D．Obama’s speech in Fudan University.