（）可被看成一种可形成暂时单链缺口（I型）或暂时双链缺口（II型）的可逆核酸酶。
参考答案：DNA拓扑酶
Mamford Industries has solid earnings that are projected to grow steadily into the foreseeable future. Which of the following is TRUE（）
A. Mamford is a growth company.
B. Mamford's stock is considered a growth stock.
C. Mamford is a growth company and its stock is a growth stock.
近年来以美国为首的西方国家在世贸组织中向发展中国家施加压力的借口主要是（）
A.技术标准问题
B.劳工标准和环境保护问题
C.原料粗加工问题
D. * * 、民主问题
