交情不深英文是什麼..?

We are just casual acquaintances.
acquaintance 解相識o既人，但唔係太熟，見 merriam webster 解釋 2b：
http://www.m-w.com/dictionary/acquaintances

我對佢認識不多
I didn't know much about him/her.

1..He/She is unknown to me.

2..I am not familiar with him/her.

交情不深 可長寫 交往時間不多,因此大家認識不深。

We are friendly relation time lessly,therefore understanding unimpressive of us.

we are not close.