yo tropezaba
I used to stumble / I was stumbling
tú tropezabas
you used to stumble / you were stumbling
él tropezaba
he used to stumble / he was stumbling
nosotros tropezábamos
we used to stumble / we were stumbling
vosotros tropezabais
you used to stumble / you were stumbling
ellos tropezaban
they used to stumble / they were stumbling