经过几个月的训练，他的体型发生了彻底的变化。

After months of training, his body shape completely ___mutated.

这些细菌在抗生素环境下会快速变异。

These bacteria can ___mutate quickly under antibiotic pressure.

导演决定修改剧本，增加了一些新角色。

The director decided to ___modify the script by adding some new characters.