多年生草本花卉,常作二年生栽培,通常每朵花有白、黄、紫三色,又名猫脸花,符合以上特征的花卉是()
A、万寿菊
B、三色堇
C、金鱼草
D、矮牵牛
参考答案:B
After the new president of the USA came to power, a new rule ________ soon. [ ]
A. came into being
B. came into use
C. came into the market
D. came into blossom
简述岩层性质对钻井有何影响?