最高位是千万位的数是______位数，一个七位数的最高位是______位．
最高位是千万位的数是八位数，一个七位数的最高位是百万位；
故答案为：八，百万．
红外激光片的吸收光谱峰值为
A．380nmB．420nmC．550nmD．633nmE．820nm
If you meet a stranger with familiar gestures, your brain is most likely to say_______.
A.“He is familiar and safe.”
B.“He is new and potentially threatening.”
C.“I like this person.”
D.“This is new, I don’t like this person.”
