闭室
参考答案：
当一翅室的各边均杯翅脉包围或仅基方于翅基本相通时，这样的翅室称闭室。
—Look ! There is a man cutting a tree on the moon.
—It _____ be true. The teacher says there are no living things on it. [ ]
A. can't
B. may not
C. mustn't
D. needn't
眼眶四壁由几块骨构成（）
A.6块
B.5块
C.7块
D.8块
E.4块
