某DNA片段中胸腺嘧啶的比例为a,则该DNA片段中含有鸟嘌呤的碱基对占所有碱基对的比例是()
A.a
B.1-2a
C.2a
D.1/2-a
参考答案:B
I've found some pictures of the most interesting places ______ you can visit during the winter holidays.
A. whereB. whichC. whatD. that
途中检查站应如何检查超限、超重车?