甾体皂苷分子结构中不含(),呈()性,故又称()皂苷。
参考答案:羧基;中;中性
Vessels are warned()in the area enclosed by pecked lines owing to the existence of numerous telegraph cables.
A.anchor
B.to anchor
C.not to anchor
D.not to anchoring
使用生长调节剂应注意哪些问题?