等差数列{an}的前n项和为Sn，若a7+a9=16，S7=7，则a12的值是（

女性，72岁，胃黏液癌，胃大部切除术后第3天患者出现意识模糊。查体：呼吸浅快，23/分钟，低流量吸氧，2L/分钟，氧饱和度96%，心率105/分钟，血压120/65mmHg，神志模糊，双侧瞳孔等大同圆，双肺呼吸音清，双下肺可闻及少量湿落音，双侧巴宾斯基征阴性。白细胞12.0×10⁹/L，中性粒细胞0.89。

需要立即做的检查有（）

A.头颅CT

B.心电图

C.D-二聚体

D.电解质

E.血糖

F.血气分析

G.X线胸片

H.肝、肾功能

关于加息政策的影响，说法不正确的是（）

A．利率上调，增加企业的融资成本，将抑制社会投资规模

B．提高利率可以抑制通货膨胀

C．利率上调，将抑制居民消费，增加储蓄用于未来消费

D．利率上调，将使得收入分配更加均衡

发生关节脱位时，应（）

A、把患者抱离现场

B、安抚患者，不能随便移动

C、自己动手，试着给就位

D、尽快帮他试着给就位

The blue of the sea is caused by the scattering of sunlight by tiny particles suspended in the water. Blue light, being of short wavelength, is scattered more efficiently than light of longer wavelengths. Although waters of the open ocean are commonly some shade of blue, green water is commonly seen near coasts, especially in tropical or subtropical regions. This is caused by yellow pigments being mixed with blue water. Phytoplankton are one source of the yellow pigment. Other microscopic plants may color the water brown or brownish-red. Near the shore, silt or sediment in suspension can give water a brownish hue. Outflow of large rivers can often be observed many miles offshore by the coloration of suspended soil particles.Marine phytoplankton (Greek for "plant wanderers") are microscopic single-celled plants that include diatoms, dinoflagellates, coccolithophorids, green algae, and blue-green algae, among others. The growth of these organisms, which photosynthesize light, depends on a delicate balance of nutrient enrichment via vertical mixing, which is often limited by the availability of nitrogen and light. Diatoms are one-celled plants with patterned glass coverings. Each glass, or silicon dioxide box, is ornamented with species-specific designs, pits, and perforations making them popular with microscopists and, more recently, electron scanning microscopists.

Which of the following is NOT a type of phytoplankton

A．Green algae.

B．Diatoms.

C．Blue-green algae.

D．Amoeba.