我国的汉字起源于商周时期的（）。

下列哪些是心绞痛的疼痛特点

A．阵发性前胸、胸骨后部痛

B．劳累或情绪激动时发作

C．可放射至心前区与左上肢

D．持续时间长，像针刺刀扎样痛

E．持续数分钟，为压榨性疼痛

有两块面积相同的小麦试验田，分别收获小麦9000kg和15000kg．已知第一块试验田每公顷的产量比第二块少3000kg，若设第一块试验田每公顷的产量为xkg，根据题意，可得方程　 　．

猪场的生产工艺流程中，一般情况下不常见的工艺流程是（）

A．二段式

B．三段式

C．四段式

D．五段式

当腹主动脉内径大于（）可诊断为腹主动脉瘤。

In December 1992 Tideville Shopping Mall repaired and improved the lighting in the mall’s parking lots, and in 1993 car thefts and attempted car thefts from those lots decreased by 76 percent from the previous year. Since potential car thieves are generally deterred by good lighting, the decrease can be attributed to these improvements.
Which of the following, if true, most hepls to strengthen the argument above

A．Both in 1992 and in 1993, most of the cars stolen from the mall’s parking lots were relatively new and expensive luxury models.

B．Most of the cars that were stolen from the mall in 1992 were stolen between 11 A.M. and 4 P.M.

C．Tideville Shopping Mall is one of only three shopping malls in the Tideville area.

D．In the town of Tideville, where the mall is located, the number of car thefts was about the same in 1993 as in 1992.

E．(E) In 1993 the number of security officers patrolling the mall’s parking lots at night was doubled.