Both Marx and Engels were (German) _____.
根据以下资料回答51~55题
第51题()起草委员会()专家委员会
第51题
Fred was playing the piano while Mary and I (sing) ________.
()优先股()股票经纪人
A series of cultural programs (hold) ____ in Shanghai to celebrate this largest national sports meeting in history.
He got to know that the earth (move) ____ around the sun at the age of four.