A、providing the impeller with balancing holes
B、the use of symmetrical impeller
C、neither A nor B
D、either A or B
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A、supplies or attempts to supply B、imposes or attempts C、complies or attempts to comply D、provides or attempts to provide
A、A.supplies or attempts to supply B、B.imposes or attempts C、C.complies or attempts to comply D、D.provides or attempts to provide
A、after every major hydrographic survey of the area covered by the chart B、when there are numerous corrections to be made or the corrections are extensive C、when a low-stock situation occurs and minor corrections are made D、every two years to update the magnetic variation information
A、An information trap is sent to the SNMP server. B、Informational and debug messages are logged to the syslog server. C、All messages are sent to the logging host, where selections are made. D、All messages from emergencies to informational are sent to the logging host.
A、An information trap is sent to the SNMP server. B、Informational and debug messages are logged to the syslog server. C、All messages are sent to the logging host, where selections are made. D、All messages from emergencies to informational are sent to the logging host.
A、On a vessel ,lines are made fast on bollards . B、On shore, lines are made fast on bollards . C、On board , lines are made fast on bitts. D、On board, lines are made fast on bollards .
A、refrigerant must be bled off the sensing line before adjustments are made B、all refrigerant must be pumped into the receiver before adjustments are made C、time must be allowed for conditions to stabilize in the evaporator before further adjustments are made D、all refrigerant must be routed through the dehydrator while changing the superheat setting
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