A. is B. are C. am D. be
单项选择题It is chairman of the department ______ the teaching staff elected him.
单项选择题I prefer ______ there doing nothing.
单项选择题It is foolish ______ such a mistake.
单项选择题No sooner had we reached the top of the mountain ______ we all sat down to rest.
单项选择题Neither Mary nor her brother ______ good at singing.