I am reading American Accent Training. I find sometimes either 'it' or 'what' at the beginning is omitted.
e.g.
It's in the bag. [tsinə bag]
What's in it. (Though labeled [w'ts ..] I only hear [tsini])
I have learned some rules about elision of /t/ and /h/, but I googled and failed to get rules about the elision at the beginning.