劳动节约型的技术进步主要是通过生物、化学技术的采用而实现的。
参考答案：错
李刚家要栽种一批树苗，这种树苗的成活率一般为80%-85%，如果要栽活2000棵树苗，那么至少应栽______棵．
Mr Smith was________to be a doctor but he became a teacher when he grew up. [ ]
A. demanded
B. supposed
C. suggested
D. agreed
