基本对一下的八种句型，每种背两三句，四级的作文肯定对拿高分...一）原因1.A number of factors are accountable for this situation。A number of factors might contribute to (lead to )(account for ) the phenomenon(problem)。2. The answer to this problem involves many factors。3. The phenomenon mainly stems from the fact that.。。4. The factors that co...
