下列说法正确的是( ) ①有化学键破坏的变化一定属于化学变化　②发生了颜色变化的

目前公认的胰腺厚度测量方法是（）。

A.下腔静脉前方测量胰头，肠系膜上静脉和脾静脉汇合处前方测量胰颈

B.腹主动脉前方测量胰体

C.脊柱或腹主动脉左缘左肾前方测量胰尾

D.以上各项均是

用所给词的正确形式。

1. When I ________(give) you a present, you must open it at once.

2. American people eat lots of ________ (hamburger) everyday.

3. Can he ________ (help) me ________ (do) the work?

4. It's too difficult ________ (understand)what you are trying ________ (say).

5. He could see the smoke ________ (rise) from the chimney (烟囱) when he

    ________ (walk) past your house at this time yesterday.

对小儿高热惊厥有效的药物是（）

A.卡马西平

B.苯妥英钠

C.地西泮

D.水合氯醛

E.苯巴比妥

简述宝石的发光性的作用。