如图所示，AB是一质量为m的均匀细直杆，A端靠在光滑的竖直墙壁上，B端置于水平地

已知等差数列{a_n}的首项为a₁，公差为d，其前n项和为S_n，若直线y＝a₁x与圆(x－2)²＋y²＝4的两个交点关于直线x＋y＋d＝0对称，则S_n＝________．

下图显示一个细胞一次分裂的细胞周期。假如以具有放射性的核苷酸供应这个细胞，这些核苷酸进入染色体的时期是

A．W期

B．X期

C．Y期

D．任意时期

关于表里同病治法，下列说法不正确的是

A．先表后里

B．先里后表

C．表实先治表

D．表里同治

E．里实先治里

You are a project manager for residential construction. As a project manager, you must be especially concerned with building codes particularly in the quality planning process. You must ensure that building codes are reflected in your project plans because ______ .

A．standards and regulations are an input to quality planning

B．quality audits serve to ensure there is compliance with regulations

C．they are a cost associated with quality initiatives

D．compliance with standards is the primary objective of quality control

芍药汤的功效是：

A．清热解毒、调和气血

B．清热解毒、凉血止痢

C．温中补虚、涩肠止泻

D．清热治痢、和中止痛

E．清热燥湿、涩肠止泻