他用刀把纸张切成细条。

He was ___slicing the paper into thin strips with a knife.

她小心翼翼地用刀片在信封上划开一条缝。

She carefully ___slit the envelope with a blade to make an opening.

她用小刀在纸箱上划开一道口子。

She was ___splitting the cardboard box with a small knife.