土的渗透系数影响因素很多，如土的种类和性质、颗粒级配、温度等。

在静息情况下，细胞膜对下列哪种离子的通透性最大

A．K⁺

B．Na⁺

C．Cl^-

D．Ca²⁺

E．Mg²⁺

Artistic Skates

Artistic roller skates are made up of a leather boot, very strong sole plate, and a jump bar that adds extra force. The boot sits a few inches above the ankle, providing more support for the foot.

Jam Skates

Jam skates are the most different roller skates because of their special low-cut design and lack of toe stop. That’s right: there is no brake. But the original jam skate design was different, resembling an artistic skate. Jam skating is more about personal expression rather than speed skating. The free-flowing movements of jam skating have been given many names. But regardless of its name, jam skating has always been about expression and passion.

Speed Skates

A speed skate resembles a shoe. The cut of the boot is lower. Speed skates typically offer lightweight plates to reduce exhaustion for skating long distances. Jam skates have preferred speed skates because they offer a similar design and freedom of movement. The most obvious difference is that a speed skate features a toe stop, unlike a jam skate that uses a toe plug.

Rhythm Skates

Rhythm skates are similar to jam skates. The difference between them lies in the boot design. In fact, the boot design looks very similar to an artistic skate, essentially providing you with the ankle support benefits of an artistic skate, but the freedom of movement of a jam skate. If you want a skate that allows you to move to the beat, which added ankle support, the rhythm skate is the ideal choice.

小题1:Which of the following is NOT a feature of jam skates?

A．They have no brake

B．They lack a toe stop

C．They have no toe plug.

D．They have a unique, low-cut design.小题2:If you want to skate to music, which of the following is the best choice?

A．Rhythm skates

B．Jam skates

C．Speed skates

D．Artistic skates小题3:Speed skates are popular with jam skates because _____.

A．they have a high boot cut

B．they allow free-flowing movement.

C．they are able to stabilize the foot

D．they can help jam skates reduce tiredness.小题4:What is a common feature of rhythm and jam skates?

A．They both offer some support for the ankles.

B．They both have a similar boot design.

C．They are both suitable for free-flowing movement.

D．They are both about personal expression and passion.小题5:What can you learn from the passage about jam skates?

A．The original jam skate design has hardly changed.

B．The original jam skate design was similar to an artistic skate.

C．Jam skates have gradually become a type of speed skate.

D．Jam skating has many names because it’s about expression and passion.

【问题4】

该图书馆无线阅览室的WLAN网搭建完成后，读者小郭需要在该阅览室公告栏上查看无线网卡的相关配置参数，并做正确设置后方可访问因特网。请结合图7-9所示的无线网卡参数的配置界面，指出读者小郭应重点从公告栏中查看哪些无线网卡的配置参数

下列哪项不是石膏的主治（）

A.肺热咳喘

B.胃火上炎所致的头痛、牙龈肿痛、口舌生疮

C.温病气分高热

D.阴虚火旺，潮热盗汗

E.疮疡不敛，湿疹，水火烫伤

渗流。