Jane is honest and never tends to hide her opinion. She must give you a(n) _____suggestion about it.  

A．abrupt

B．ambiguous

C．straightforward

D．hesitant

说出下列农业生产措施所依据的生物学原理。（4分）

⑴合理密植主要根据                                原理。

⑵中耕松土主要根据                                原理。

⑶种植棉花、西红柿适时地摘除主干上的顶芽根据                    原理。

⑷幼苗移栽一般在阴天或傍晚进行主要根据                           原理。