问题
选择题
Lady Gaga has put off her concerts because of the difficulties by the ongoing strikes.
A．caused
B．causing
C．to be caused
D．having caused
答案
答案：A
题目分析：句意：Lady Gaga推迟了由于正在进行的罢工导致的困难。这里需要定语修饰difficulties ，因为difficulties和cause是动宾关系，所以用过去分词做定语，选A。