What is the minimum period of time that the air supply for a self-contained breathing apparatus is required to last?________.A.10 minutesB.20 minutesC.30 minutesD.90 minutes

题目

What is the minimum period of time that the air supply for a self-contained breathing apparatus is required to last?________.

A.10 minutes

B.20 minutes

C.30 minutes

D.90 minutes

相似考题

1.When voltage and current developed in an AC circuit reach their peak values at the same time, the power factor is _____.A.laggingB.leadingC.maximumD.minimum

2.The majority of nurses are women, but in the higher ranks of the medical professionwomen are in a__________.A.minority B.scarcity C.rarity D.minimum

3.在 Windows 中，运行（请作答此空）命令得到下图所示结果。以下关于该结果的叙述中，错误的是（）。Pinging 59.74.111.8 with 32 bytes of data:Reply from 59.74.111.8: bytes=32 time=3ms TTL=60Reply from 59.74.111.8: bytes=32 time=5ms TTL=60Reply from 59.74.111.8: bytes=32 time=3ms TTL=60Reply from 59.74.111.8: bytes=32 time=5ms TTL=60Ping statistics for 59.74.111.8: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),Approximate round trip times in milli-seconds: Minimum = 3ms, Maximum = 5ms, Average = 4msA.ipconfig/all B.ping C.netstat D.nslookup

4.Cost，minimum 最低成本

参考答案和解析
正确答案：C
自己式呼吸器的时间是最少30分钟。
更多“What is the minimum period of time that the air supply for a self－contained breathing appa ”相关问题

  • 第1题：

    在 Windows 中，运行（ ）命令得到下图所示结果。以下关于该结果的叙述中，错误的是（ ）。

    Pinging 59.74.111.8 with 32 bytes of data:

    Reply from 59.74.111.8: bytes=32 time=3ms TTL=60

    Reply from 59.74.111.8: bytes=32 time=5ms TTL=60

    Reply from 59.74.111.8: bytes=32 time=3ms TTL=60

    Reply from 59.74.111.8: bytes=32 time=5ms TTL=60

    Ping statistics for 59.74.111.8:

    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

    Approximate round trip times in milli-seconds:

    Minimum = 3ms, Maximum = 5ms, Average = 4ms

    A.ipconfig/all
    B.ping
    C.netstat
    D.nslookup

    答案：B
    解析：
    ping命令的作用的检查两个机器之间的连通性的。

  • 第2题：

    8、基于initial语句产生普通时钟信号， parameter clk_period = 10; reg clk; initial begin clk = 0; ________________; end

    A．always #(clk_period/2) clk = ~clk

    B．forever #(clk_period/2) clk = ~clk

    C．always #(clk_period) clk = ~clk

    D．forever #(clk_period) clk = ~clk


    always #(clk_period/2) clk = ~clk;forever #(clk_period/2) clk = ~clk

  • 第3题：

    在端口PHI1创建时钟周期为10，上升在5.0，下降在9.5

    A．create_clock “PHI1” –period 10 –waveform {5.0 9.5}

    B．create_clock “PHI1” period 10 –waveform {5.0 9.5}

    C．create_clock “PHI1” period 10 waveform {5.0 9.5}

    D．create_clock “PHI1” –period 10 –waveform {1 2}


    create_clock “PHI1” –period 10 –waveform {5.0 9.5}

  • 第4题：

    在 Windows 中，运行（请作答此空）命令得到下图所示结果。Pinging 59.74.111.8 with 32 bytes of data:Reply from 59.74.111.8: bytes=32 time=3ms TTL=60Reply from 59.74.111.8: bytes=32 time=5ms TTL=60Reply from 59.74.111.8: bytes=32 time=3ms TTL=60Reply from 59.74.111.8: bytes=32 time=5ms TTL=60Ping statistics for 59.74.111.8: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),Approximate round trip times in milli-seconds:Minimum = 3ms, Maximum = 5ms, Average = 4ms）

    A.ipconfig/all
    B.ping
    C.netstat
    D.nslookup

    答案：B
    解析：
    ping命令的作用的检查两个机器之间的连通性的。

  • 第5题：

    基于initial语句产生普通时钟信号， parameter clk_period = 10; reg clk; initial begin clk = 0; ________________; end

    A．always #(clk_period/2) clk = ~clk

    B．forever #(clk_period/2) clk = ~clk

    C．always #(clk_period) clk = ~clk

    D．forever #(clk_period) clk = ~clk


    always #(clk_period/2) clk = ~clk;forever #(clk_period/2) clk = ~clk

  • 第6题：

    以下关于VDB函数的语法正确的是（）。

    A．VDB（cost，salvage，life，period，factor）

    B．VDB（cost，salvage，life，period，month）

    C．VDB（cost，salvage，life，per）

    D．VDB（cost，salvage，life，start-period，end-period，factor，no-switch）


    VDB（cost，salvage，life，start-period，end-period，factor，no-switch）

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