We run long _______.

In order to safeguard（保证）the education of all Hope Chinese Scholl（HCS）students and the normal running of the school, the following rules should be followed:
★ Be quiet in classroom and hallways. Do not run or shout in classrooms or hallways.
★ Do not drink or eat in classrooms or hallways.
★ Stay in the school during school time as well as rest time. Do not leave the school or play out of the school area during school time. This includes rest time.
★ Do not scribble on any desks or walls.
★ Be respectful（尊敬）to teachers and parents.
★ Help teachers and other students to keep the classroom clean. Do not move desks, chairs, and other furniture in the classroom without the teacher's instructions.

如图是小红利用小瓶、橡皮塞和玻璃管自制的液体温度计。该温度计是根据液体热胀冷缩的规律来工作的。实际使用中发现该温度计玻璃管中液柱变化不明显，导致示数不准确。对此，请你提出一条改进的建议：____ 。