【多选题】下列差分方程所描述的系统不是线性系统的是( )。
【判断题】He tried hardly but failed to finish his work in time.
【简答题】He tried (hard, hardly) but failed to finish his work in time.
【单选题】He had hardly had time to finish the sound-recording ______ he turned off the radio.
【单选题】Hardly ______ his speech ______ the audience started cheering.
B.
does he finish; before
C.
has he finished; while
【简答题】Hardly he (finish) ______ his speech when the audience started sheering.