I began to feel ________ in the new school when I saw some familiar faces.
A.at homeB.at heartC.at willD.at sight在线课程A
解析：
此题考查固定短语的用法。feel at home意为：to feel relaxed and comfortable in a particular place or situation，即舒服自在，无拘束。其余三项和feel构不成固定短语，意思也不符。at heart意为“在心底，实际上”；
at will意为“随意地”；
at sight意为“一见就……”。故选A。