题干
The famous pop singer has been the ____________ of fierce criticism in the country’s media since he was found taking drugs.
A：aim
B：target
C：focu
D：goal
答案(点此获取答案解析）
B
，则该DNA分子连续复制两次共需游离的胸腺嘧啶脱氧核苷酸（ ）