语法与词汇 Under the guidance of their teacher, the pupils are building a model boat _____ by steam.

【正确答案】 D

【答案解析】句意：在老师的指导下，学生们在造一艘蒸汽模型船。propel推进，推动。 tow（用绳索或链子）拖，拉。 press按，压。toss扔，抛。