【单选题】The teacher has failed to ________ his students to read more.
【简答题】A teacher has a wide (vary) ______of duties.
【简答题】What if a child has poor chemistry with the teacher?
【简答题】载波监听多路访问/冲突检测的原理可以概括为先听后发,(),冲突停发,随机重发。
【单选题】Only when __________________ permission _______________ allowed to enter the lab.
A.
a teacher has given; are the students
B.
has a teacher given; are the students.
C.
has a teacher given; the students are
D.
a teacher has given; the students are
【简答题】当电动机低于额定转速时应采用恒转速方式调速。( )