【简答题】喷泉水池的水口至少有______、给水口、______和溢水口
【单选题】Which statement about entering into a tank which has been sealed for a long time is TRUE ________.
A.
The tank should be tested only once to ensure the oxygen content is at least 14% before entry
B.
The tank must be tested at frequent intervals to ensure that hazardous gasses have not regenerated
C.
The tank need not be tested for oxygen content if it is ventilated for more than 24 hours
D.
If the oxygen content tests at less than 12% you should wear an approved gas mask
【判断题】有向图如果存在回路,则要素所对应的行与列在可达矩阵中相同,且可缩减( )
【单选题】Which statement about buying things for yourself is true?
A.
You feel good for a long time.
B.
You feel good for a short time
【单选题】直流电路中某支路电流和电压为关联参考方向,电流绝对值大小为2A、电压绝对值大小为12V,则下列选项正确的是()。
C.
可以确定该支路的功率绝对值大小为24W,但无法确定支路是吸收24W还是发出24W。
【单选题】直流电路中某支路电流和电压为非关联参考方向,电流的绝对值大小为4A、电压的绝对值大小为8V,则下列选项正确的是()。
C.
可以确定该支路功率绝对值大小为32W,但无法确定支路是吸收32W还是发出32W。
【单选题】支付宝实名认证( V1 )等级,需要的资料有( )。
【单选题】Which statement is true for cellulose, but not true for protein?
A.
It is found in cell surface membranes.
B.
It is synthesised from identical sub-units
C.
It is used as an energy source.
D.
It may be a structural component.