Capitalizing in Direct Quotations

Capitalize the first word in a direct quotation that is a full sentence, but do not use a capital to continue a quote after an interruption. The following example of an interrupted quotation is punctuated correctly:

“I was given a ticket,” explained Bob, “by a motorcycle cop hiding behind a parked car.”

Which sentence is correct? “When my parents came to the United States, after World war II ,” my History teacher said, “Neither of them spoke a word of English.” “Since I speak fluent German,” my Aunt Anna said, “let me do the talking when we get to the hotel.”