Test your proofreading skills

Borrowed from Writers' Forum, the extract below contains 20 errors. Can you find them?

'The first thing the groundkeeper saw when he went to tend to the small cemetery behind St. Sebastians was the body that someone had forgotton to bury.
She was lying on top of a grave her head pressed close to the headstone, her arms crossed over her stomach. she was almost as white as the seven faded granite markers that surrounded her. The groundskeeper takes a deep breath, dropped her trowel, and crossed himself. He inched toward the body and leaned over, casting a shadow.
Somewere overhead a gull screamed, and as the womans eyes flew open, the groundskeeper turned and ran threw the iron gate into the dizzying streets of los Angeles.
The woman looked into the sky. She did not know where she was, but it was quiet; and since her head was pounding, she was grateful She tried to remember how she had gotten their in the first place.
Sitting up, she touched the gravestone and squinted as the letters dipped and blurred before eyes. She pulled herself to her feet and, balanced against the stone for support. The she leaned over and wretched, clutching her stomach and blinding back tears at the pain shooting through her temples.
"A church" she said aloud, jumping at the pitch of her own voice. This is a church."
She walked to the gate and stared as the cars and buses going by.
She had taken three steps away from the church before she realized she did not know where she was supposed to go. "Think," she commanded herself. She put a hand to her forehead and feels the slip of her own blood.'

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