苏辙的《涂山》“娶妇山中不肯留，会朝山下万诸侯。古人辛苦今为谁，只见清淮入海流。

根据《中华人民共和国合同法》，由于债权人的原因致使债务人难以履行债务时，债务人可以将标的物交给有关机关保存，以此消灭合同的行为称为( )。

A．留置
B．保全
C．质押
D．提存

为了考察资金的利用效率，可采用( )指标作为净现值的补充指标。

A．试算折现率
B．内部收益率
C．外部收益率
D．净现值率

—Bob speaks Chinese quite well.

—Yes, _____. Both of them practise ______ Chinese every day. [ ]

A. so does Tom, speaking

B. Tom does so, to speak

C. so Tom does, speaking

D. so does Tom, to speak.

In this lecture, I can only give you a purely ________ view of how we can live life to the full and make

some suggestions about the future. [ ]

A. private  

B. personal

C. unique  

D. different

在下列条件下，播种在土壤里的种子，可以萌发的是[ ]

A．种子的种皮和胚受到较多的损伤

B．种子处于休眠状态

C．土壤里的温度和湿度不适

D．土壤板结