If p and q are statements, which of the following formulas is tautological? ()
A. ┐ (p→q)∧q
B. (p∨q)→p∧q
C. (q∧(p→q))→p
D. ((p→q)∧p)→q
Press ______ button, and you can get service without paying for it.
A. 911
B. Tow
Call
D. Tow and 911
《中国药典》2000年版一部规定,麻黄中生物碱的含量测定的采用