可以用 "call every day" 来表示天天打电话。这个短语的来源是很显然的，"call" 是指打电话的意思，"every day" 是指每一天。
下面是一些例句：
I call my mom every day. (我天天给妈妈打电话。)
He calls his girlfriend every day. (他天天给女朋友打电话。)
She calls her best friend every day. (她天天给好朋友打电话。)
你也可以用 "phone" 来替换 "call"，表示打电话：
I phone my dad every day. (我天天给爸爸打电话。)
They phone their grandparents every day. (他们天天给祖父母打电话。)
希望这些例句能帮助你理解如何用英语表示天天打电话的意思。