从田间束叶长度判断用药时间，被害叶片处于束叶期至（）厘米左右。
A、3—4cm
B、6—7cm
C、8-10cm
D、10cm以上
参考答案：A
Greatly moved by what she did, . [ ]
A. I could hardly hold back my tears
B. my heart was full of gratefulness
C. my eyes were filled with tears
D. tears came to my eyes
影响洗涤作用的因素有哪些？哪些是主要因素？哪些是次要因素？为什么？
