It's already 8:00 and my mother ____ here any moment

be likely to "很有可能\易于"的意思
如：

1、Noticing that there was likely to be trouble, they sneaked away.
他们看到有可能发生麻烦，就悄悄离开了。

2. But the boss said we were likely to work overtime today.
但是老板说我们今天很可能要加班。

3. You will be likely to get there before 8 o'clock.
你很有可能在8点钟之前赶到那里。

will probably be here
你看看词性好不好
to 的后面都没有be