【单选题】Recent research into aging suggests that the body's defense mechanisms may lose the ability to distinguish what is alien.
【单选题】According to this passage, family stability depends on______.
A.
the couples' earning ability
B.
the relative balance between the benefits and costs of marriage
C.
how much possessions the couple have before marriage
D.
a network of social and legal support
【单选题】The increase in international trade has resulted in a demand for employees with the ability to communicate in a foreign language,
A.
国际贸易的增加要求员工具备使用外语进行交际的能力。
C.
国际贸易增加了员工使用外语的要求,也提高了他们的外语能力。
D.
国际贸易增加了对员工使用外语交际能力的要求。
【单选题】Observations of cetaceans in the wild have provided some insights on their learning abilities. Several bottlenose dolphins off western Australia, for instance, have been observed carrying large cone-s...
A.
It is not appropriate to judge cetacean intelligence in human terms.
B.
Cetaceans probably possess a mental sophistication that is as complex as that of humans.
C.
Although cetaceans may appear to be intelligent, they have fewer problem-solving skills than most animals,
D.
Their ability to learn American Sign Language indicates that cetaceans have a high level of intelligence.
【单选题】What is the most important aspect for entrants in the competition?