植入开始的时间是（）。
A、受精后第5-6天
B、受精后第2-3天
C、受精后第1-3天
D、受精后第11-12天
参考答案：A
趣味成语。（在下列成语中填写人体部位或器官的名称）
Our English teacher is _______ and never _______ to us, so we like her very much. [ ]
A .funny; friendly
B .funny; unfriendly
C. fun; friend
D. fun; unfriendly
