研究人员通过体外选择技术筛选出了具有催化活性的DNA分子。

The team applied ___IVS to isolate DNA molecules with catalytic activity.

科学家们正在研究这些IVSs在基因表达中的作用。

Scientists are studying the role of these ___IVSs in gene expression.

医生建议她在手术后接受静脉输液以补充体液。

The doctor recommended that she receive ___IVS after the surgery to replenish fluids.