【简答题】构建由小写英文字母组成的向量,每个英文字母重复100次,赋值给y,可写作:y<-_____________________< /div>
【单选题】听力原文: In the United States the family plays an important role in most holiday activities. November is National Adoption Month. We visit with an American family that has an extra special reason to cele...
A.
Holiday celebrations in the United States often ignore the importance of family.
B.
Holiday celebrations in the United States often are centered around the family.
C.
Holiday celebrations in the United States often are centered around work.
D.
Holiday celebrations in the United States often are centered around animals.
【单选题】What is the function of a carbon sink?
A.
It regulates carbon emissions from human activities
B.
It measures the amount of carbon dioxide in the ecosystem
C.
It collects and drains seasonal rainwater from the soil
D.
It removes carbon dioxide naturally from the atmosphere