问题
选择题
Some children were seen _______in the garden all the morning. It must have been _______who picked the flowers.
A．playing; they
B．to play; they
C．playing; them
D．play; them
答案
答案：A
考查非谓语动词与人称代词。句意：一些孩子被看到整个上午都在花园里玩。肯定是他们拔了这些花。现在分词做状语表示句子主语正在进行的伴随性动作。下文人称代词为从句的逻辑主语，故需用主格形式，选A。