DNA分子的双链在复制时解旋,这时下述哪一对碱基从氢键处分开? [ ]
A.腺嘌呤和胸腺嘧啶
B.鸟嘌呤和尿嘧啶
C.鸟嘌呤和胸腺嘧啶
D.腺嘌呤和胞嘧啶
答案:A
Which of the following statements is NOT true
A.Aspirin can relieve pain.
B.Aspirin can reduce fever.
C.Aspirin can relieve inflammation.
D.Aspirin can reduce stomach lining.
UPS的使用环境要求清洁、少尘、干燥,通常在()都能正常工作。不应把强磁性物体放在UPS上,否则会导致UPS工作不正常或损坏机器。
A.0℃~20℃
B.0℃~30℃
C.0℃~40℃
D.0℃~50℃