问题
选择题
Some English scientists are identifying problems ____ technology in the 21st century. If solved, the solutions could change the world.
A．facing
B．faced
C．being faced
D．having faced
答案
答案：A
考查非谓语动词。句中facing technology in the 21st century作定语，修饰名词problems，之间为主动关系，故选A。
