题目

_______ by the problem that was put forward at the meeting，the people in the audience had ________ looks on their faces. A. Puzzled; puzzling   B. Puzzled; puzzled   C. Puzzling; puzzling     D. Puzzling; puzzled   答案：B如图把含有生长素的琼脂小块，分别放在甲、乙、丙三琼脂小块株幼苗切面端的不同位置上，然后从左侧给予光照。此实验的结果不会（     ）A．甲向右侧弯曲生长 B．乙直立生长 C．丙向左侧弯曲生长 D．甲、乙、丙都弯向光源生长