So doctors must use stronger, "second line" drugs when the first ones fail.

VOA: special.2009.03.25

let's look at the next one here, first or is that second line?

或者说是下一行，好的，如果last减去？

麻省理工公开课 - 计算机科学及编程导论课程节选

The strain is impervious to a wide array of first and second-line drugs.

NPR: TB Traveler Exposes Diagnosis Problems

For confirmed XDR-TB, in which the bacterium is resistant to the most potent first- and second-line TB medicines, the WHO recommends that a proper combination of any medicine left among those available, dictated by knowledge of susceptibility, should be used.

WSJ: The WHO Supports India's Fight Against MDR-TB �� Letters to the Editor

Mr. BROWN: I'll tell you, what happened over the weekend with Usain Bolt winning the men's 100 and Shelley Ann Fraser winning the women's 100 and having the first three ladies across the line, and having first, second and second - it has been celebrated a whole lot here in Jamaica.

NPR: Jamaicans Revel In 100M Olympic Triumphs