地下卷材防水层未作保护结构前，应保持地下水位低于卷材底部不少于（）。A．200mm

建设项目污水排放量为15000m³/d，污水中污染物就一种，需预测浓度的水质参数为8个，排水进入一条多年平均流量为100m³/s的河流，该河流环境质量标准执行III类。其地面水环境影响评价应按( )开展工作。

A．一级
B．二级
C．三级
D．四级

语法填空。

     The Dragon Boat Festival is celebrated on the fifth day of the fifth month according to the Chinese

calendar.For thousands of years,the festival 1._____(mark) by eating zong zi and racing dragon boats

in honour of Qu Yuan,who is said to have committed suicide(自杀) by drowning himself.

     Qu was a minister of the State of Chu 2._____(situate) in the presentday Hunan and Hubei provinces,

during the Warring States Period (战国时期)．He was upright,loyal and highly respected.3._____,he

was dismissed from office.4._____(realize) that the country was in the hands of evil officials,Qu leapt

into River Miluo on the fifth day of the fifth month.Nearby fishermen rushed over to save him but were

5._____(able) to recover his body.

     The people of Chu 6._____mourned Qu's death threw rice into the river to feed his ghost 7._____

year on the day of his death.But one year,the spirit of Qu appeared and told the mourners that a huge

reptile (爬行动物)in the river had stolen the rice.The spirit then advised 8._____to wrap the rice and

bind it 9._____throwing it into the river.

     During the Duanwu Festival,zong zi is eaten to symbolize (象征,表示) the rice offerings to Qu.And

the dragonboat races symbolize 10._____many attempts to rescue and recover Qu's body.

PE管电熔鞍形分支或鞍形三通的出口应（）管材的中心线。

A、位于

B、平行

C、垂直于

D、横向于

散热器盖的蒸气阀弹簧过软，会使（）。

A.散热器内气压过低

B.散热器芯管容易被压坏

C.散热器内气压过高

D.冷却水不易沸腾

正弦输入函数r（t）的数学表达式是（）

A.r（t）=sinwtr

B.r（t）=sin（wt+θ）

C.r（t）=Asin（wt+θ）

D.r（t）=Acos（wt+θ）