QUES: When a disk shaped object started pacing the plane and flying around it Everyone in the schoolyard stopped playing and started pointing at it

correct the punctuation.

CORRECTED: When a disk shaped object started pacing the plane and flying around it. Everyone in the schoolyard stopped playing and started pointing at it.

QUES: The HCV epidemic remains a global threat with 80 of newly infected patients developing a chronic infection putting them at risk of cirrhosis liver failure or hepatocellular carcinoma

correct the punctuation.

CORRECTED: The HCV epidemic remains a global threat, with 80% of newly infected patients developing a chronic infection, putting them at risk of cirrhosis, liver failure or hepatocellular carcinoma.

QUES: their cruise along a natural romantic coastline

correct the punctuation.

CORRECTED:
their cruise, along a natural, romantic coastline.