为提高数控机床的定位精度和运动平稳性，目前普遍使用摩擦系数较小的（）。 A.普通滑动

看图填词。

     One afternoon Mary and her five-year-old brother Tom (1)            playing hide-and-seek in the street just

outside the (2)            office. Mary had covered her eyes and was counting up to ten (3)            Tom found

that the small door of the mail-box (邮箱) was left open. The postman (邮递员) had just taken all the

(4)            out and gone into the post office. Tom went into the mail-box and pull the door from inside so

hard (5)            it was locked (被锁上). When he knew what he had done, he became frightened and started (6)           . (7)           the same time Mary was (8)           for him everywhere but could not (9)           him.

When he heard her little brother crying in the mail-box, she quickly ran to tell the postman about it. The man

hurried out to open the (10)           of the mail-box and Tom got out.

无排卵性功血患者子宫出血量多的机制不包括

A．血内纤溶酶活化，引起纤维蛋白裂解，加重出血

B．雌激素长时间持续作用而缺乏孕激素拮抗，子宫内膜不受限制地增生

C．子宫内膜螺旋小动脉收缩乏力，使出血时间长，不易自止

D．子宫内膜不能同步脱落，致使一处修复，另一处破裂出血

E．长时间大量雌激素作用使子宫腔增大，内膜出血面积增大

下列可能造成第三者责任损失的是（）。

A.投资风险和进度风险

B.进度风险和质量风险

C.质量风险和安全风险

D.安全风险和投资风险

煤中全水分符号为（），固定碳符号为（），煤的挥发分符号为（），一个煤样挥发分含量为27%，则该煤样属于（）煤。

在用指数平滑法进行市场预测时，如果目的在于用新的指数平滑平均数去反映时间序列中所包含的长期趋势，那么平滑常数a最合适的是（）

A、0.1

B、0.5

C、0.9

D、1.0