Jenny, the new comer, has earned not only the trust of her classmates but also ______ of her teachers.

A．one

B．ones

C．that

D．those

离心泵轴封的作用是（）

A、承受叶轮与泵壳接缝处的磨擦

B、减小水力损失

C、防止外界空气侵入或泵内液体外漏

D、防止内漏