Subject + 试 + 了 + (试) + Object
试 (shì) is a verb meaning "to try" or "to attempt." It is often used with 了 to indicate that an attempt was made. For example, 他试了试门 means "He tried the door."
你可以先试一下这双鞋合不合脚。
Nǐ kěyǐ xiān shì yīxià zhè shuāng xié hé bù hé jiǎo.
You can try these shoes first to see if they fit.
我试了好几次,还是打不开这个瓶盖。
Wǒ shì le hǎo jǐ cì, háishì dǎ bù kāi zhège píng gài.
I tried several times but still couldn't open this bottle cap.
她试了试水温,觉得刚刚好。
Tā shì le shì shuǐwēn, juéde gānggāng hǎo.
She tested the water temperature and felt it was just right.