3 sentences

1. 手握电筒让光线直射在一张白纸上。

   shǒu wò diàn​tǒng ràng guāng​xiàn zhí​shè zài yī zhāng bái​zhǐ shang.

   Hold the flashlight so that the beam shines straight down on a sheet of white paper.

   Source: UM-Corpus: Education

2. 拿出一张白纸，在顶部写下你想要学习的主题。

   ná chū yī zhāng bái​zhǐ, zài dǐng​bù xiě xia nǐ xiǎng​yào xué​xí de zhǔ​tí.

   Take out a blank sheet of paper and write the subject you want to learn at the top.

   Source: CCMatrix

3. 有时候，也可以拿出一张白纸，把自己的想法写下来。

   yǒu shí​hou, yě kě​yǐ ná chū yī zhāng bái​zhǐ, bǎ zì​jǐ de xiǎng​fa xiě xià​lai.

   Sometimes, you can also take out a blank sheet of paper and write down your thoughts.

   Source: CCMatrix