探究金属活动性顺序时，将锌粒放入硫酸铜溶液中，锌粒表面有紫红色物质析出，还有无色

如图所示，若太阳与水平方向成60°入射，要利用平面镜使太阳光沿竖直照亮井底，请通过作图的

方法确定平面镜位置，并标求出镜面与水平方向的夹角为       

下列哪种药物不会引起血清丙氨酸氨基转移酶(ALT、GPT)升高( )。

A．克林霉素

B．氟康唑

C．硝苯地平

D．阿昔洛韦

E．异烟肼

如图所示，两光滑导轨相距为L，倾斜放置，与水平地面夹角为θ，上端接一电容为C的电容器。导轨上有一质量为m长为L的导体棒平行地面放置，导体棒离地面的高度为h，磁感强度为B的匀强磁场与两导轨所决定的平面垂直，开始时电容器不带电。将导体棒由静止释放，整个电路电阻不计，则（    ）

A．导体棒先做加速运动，后作匀速运动

B．导体棒一直做匀加速直线运动，加速度为

C．导体棒落地时瞬时速度

D．导体棒下落中减少的重力势能转化为动能，机械能守恒

斜拉索式结构跨越适用于单跨长度大于或等于150m的大型油气管线跨越工程。

Certificates are (66) documents attesting to the (67) of a public key to an individual or other entity. They allow verification of the claim that a given public key does in fact belong to a given individual. Certificates help prevent someone from using a phony key to (68) someone else. In their simplest form, Certificates contain a public key and a name. As commonly used, a certificate also contains an (69) date, the name, of the CA that issued the certificate, a serial number, and perhaps other information. Most importantly, it contains the digital (70) of the certificate issuer. The most widely accepted format for certificates is X.509, thus, Certificates can be read or written by any application complying with X.509.

A．text

B．data

C．digital

D．structured