有以下几种物质①干燥的食盐晶体 ②液态氯化氢 ③水银 ④蔗糖 ⑤CO₂ ⑥KNO₃溶液 ⑦氯气，填空回答（填序号）：以上物质中能导电的是____ ；属于电解质的是　____ ；属于非电解质的是____ ．

天然气根据成分不同分为贫气和富气，贫气中甲烷的含量较多，富气中乙烷、丙烷、丁烷的含量相对高一些．若要将它们液化，下列说法正确的是（　　）

根据如图所示实验分析得出的结论中，不正确的是（　　）

（2016•四川）设直线l₁，l₂分别是函数f（x）= $\{\begin{array}{l}-\ln x,0<x<1\\ \ln x,x>1\end{array}$ 图象上点P₁，P₂处的切线，l₁与l₂垂直相交于点P，且l₁，l₂分别与y轴相交于点A，B，则△PAB的面积的取值范围是（　　）

语法填空

    Do you like travelling? Staying ____ (health) while ____ (travel) can help to ensure your trip is a happy and enjoyable one. ____ you are travelling abroad, here are the tips you need to make your trip much ____ (easy):

    Make sure you have got signed passport(护照) and visas. Also, before you go, fill in the emergency information page of your passport! Make two copies of your passport identification page. This will help a lot if your passport ____ (steal). Leave one copy at home with friends or relatives. Carry the other ____ you in a separate place from your passport.

    Read the Public Announcements or Travel Warnings for the countries you plan to visit. Get yourself familiar with local laws and customs of the countries to ____ you are travelling.

    Leave a copy of your itinerary(旅行日程) with family or friends at home so that you can be contacted in case of an emergency.

    Do not accept packages from strangers. Do not carry too much money or ____ (necessary) credit cards. If we make enough____ (prepare), we will succeed. Have ____ good time!