1.选择题- (共2题)
2.几位同学在探索pH对α-淀粉酶活性的影响时，设计的实验方案如下。其中操作及顺序最合理的是 （ ）
①在三个试管中各加入可溶性淀粉溶液2 mL
②在三个试管中各加入新鲜的α-淀粉酶溶液1mL
③置于适宜温度下保温5min
④分别置于100℃、60℃、0℃环境中保温5min
⑤加入斐林试剂后，水浴加热，观察现象
⑥将试管中溶液的pH分别调到3、7、11，保持5min
①在三个试管中各加入可溶性淀粉溶液2 mL
②在三个试管中各加入新鲜的α-淀粉酶溶液1mL
③置于适宜温度下保温5min
④分别置于100℃、60℃、0℃环境中保温5min
⑤加入斐林试剂后，水浴加热，观察现象
⑥将试管中溶液的pH分别调到3、7、11，保持5min
2.单项选择- (共5题)
3.
____I explained on the phone, your request will be considered at the next meeting.
| A．When | B．After |
| C．As | D．Since |
4.
The course about Chinese food attracts over 100 students per year, _______ up to half are from overseas.
| A．in which | B．of whom |
| C．with which | D．for whom |
5.
It was an exciting moment for these football fans this year,________for the first time in years their team won the World Cup.
| A．that | B．while |
| C．which | D．when |
6.
The book was written in 1946, ____ the education system has witnessed great changes.
| A．when | B．during which | C．since then | D．since when |
试卷分析
-
【1】题量占比
选择题:(2道)
单项选择:(5道)
-
【2】：难度分析
1星难题：0
2星难题：0
3星难题：0
4星难题：1
5星难题：0
6星难题：1
7星难题：0
8星难题：1
9星难题：2