_______it is to jump out of an airplane at 10,000 feet!

A．What an exciting experience

B．How exciting experience

C．How an exciting experience

D．What exciting experience

取甲、乙两个暖水瓶，甲瓶装有萌发的种子，乙瓶装有与甲瓶等量的煮熟的种子．两瓶均用插有温度计的橡皮塞塞严，置于温暖的地方，几小时后看到的现象是（　　）

A．甲瓶温度下降，乙瓶温度升高

B．甲瓶温度升高，乙瓶温度不变

C．甲、乙两瓶温度都升高

D．甲、乙两瓶温度都不变