题目

任务型阅读，阅读下面短文，根据短文内容完成下列各题。 In the past, many students practiced English with their pen friends — they sent letters to people all around the world. However, we now send emails to others and chat with people who live quite far away on the Internet. Here’s some advice on how to succeed in your online language exchanges: ▲ How to start a conversation when speaking English online When you speak to somebody online, start by asking “Yes or No” questions. Use questions such as “Do you like …?” or “Can you …?” or “Have y设NA为阿伏加德罗常数的数值，下列说法正确的是（ ）A．1 mol/L NH4Cl溶液中，NH4＋的数目小于NA B．常温常压下，8g CH4含有电子数目5NAC．12g NaHSO4晶体中含有0.2 NA个阳离子D．78g苯含有C=C双键的数目为3NA