P-P间期在心电图上有15个小格,其心率是()。
A.60次/min
B.70次/min
C.80次/min
D.90次/min
E.100次/min
参考答案:E
Aunt Li ________ the babies very well while their parents were away. [ ]
A. looked at
B. looked like
C. looked up
D. looked after
在大陆地壳表面,由风化残积物和土壤构成的松散薄壳称为古风化壳.