そこで母親は考えました。

so; accordingly; now; then; thereupon; therefore

mother

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

to think about; to take into consideration; to ponder; to reflect; to try to come at a conclusion; to think over (something); to intend; to decide (to do); to plan; to come up with; to devise; to scheme; to predict; to anticipate; to expect; to suspect; to doubt; to consider (somebody to be something); to look on