i.CO(g)+2H₂(g) CH₃OH(g)   ∆H₁=−90.1kJ·mol⁻¹

ii.2CH₃OH(g) CH₃OCH₃(g)+H₂O(g)   ∆H₂=−24.5kJ·mol⁻¹

当其他条件相同时，由H₂和CO直接制备二甲醚的反应中，CO平衡转化率随条件X 的变化曲线如右图所示。下列说法正确的是(   )

A

    I love to go biking! Two years ago I bought an exercise bike(健身脚踏车)．But soon I got bored with being at home, so I bought a used bike and started going for short rides．Now I plan day trips in my neighborhood．When you drive a car, you miss many things．It's surprising how much more you can see when you're biking．

    —Maggie

    My favorite thing to do on the weekend is to go to the beach．The beach is beautiful all through the year．I usually drive there．If the weather is cold；I wear some warm clothes and go for long walks on the beach．When the weather is hot，I enjoy swimming or lust lying in the sun.

一Barbara

    On the weekend I like to read books．If the weather is nice．I'll take a good book to the park and stay there reading for hours．I think there's nothing as enjoyable as reading a good book．

    一Bill

    Weekends are for going hiking(徒步旅行)with my parents．We live near some beautiful mountains．Sometimes we camp out at night．We really enjoy cooking dinner over a campfire and spending a night under the stars!

    一Sara