$1$ Look at these examples. In each sentence, which verb form describes the earlier action or event?

$1$ lassumed it had spread through your whole office.

$2$ After Chris had texted me$,$ I made other appointments for today.

$3$ She said she'd received it$.$

$4$ I was sure l$\text{'}$d circled the plant in the garden centre catalogue.

$5$ By the time I got to the office, the catalogue had disappeared.

$6$ I knew something had gone wrong but I couldn't imagine what.

The past perfect is often used after past simple verbs describing speech and thoughts: said told thought was sure assumed knew noticed realised...