电/光转换如何实现？

Researchers at the University of Arizona, led by Teresa Cummins, conducted an exploratory study on the online learning modules, designed to supplement hands-on classes taught by local experts and supported by an overview text, to help users increase their understanding of key concepts in the Arizona Master Watershed Steward program. They also sought to determine whether program participants would use the non-compulsory modules.

Their evaluation revealed that module users increased their understanding of key watershed concepts; participants in the evaluation demonstrated a 30 percent increase in content knowledge following module use. Additionally, 70 percent of participants retained this knowledge through a two-month follow-up test.

A follow-up survey showed that approximately half of the participants returned to the online modules on their own; several of these users returned several times and spent multiple hours per session. Comments from the follow-up survey suggested that the users accessed the site either as they had the time or as they needed the information.

Online usage statistics indicated participants continued to visit the site for many months following the modules’ release and advertisement. Though many visits were very brief (a single pageview; only a couple of seconds), visitors with many returns to the site and/or long visits appeared to be working through the modules.

One participant stated, "My brain can only hold so much information; the modules keep information on-hand." Other participants commented that the modules were "more interesting and interactive" than the text material, and a "very effective tool" and "a great resource to the Master Watershed Steward community."

The Arizona Master Watershed Steward program, sponsored by University of Arizona, prepares adults to serve as volunteers in the conservation of water resources and the protection, restoration, and monitoring of their watersheds. The modules were intended to reinforce concepts covered in classes and further engage participants in the learning process.

One key finding was that the modules were not clearly preferred by users over in-person instruction. One participant stated, "For me, they are just another avenue for learning, a supplement or additional reference. I prefer in person and real hands-on learning." Other participants similarly expressed their desire for hands-on and face-to-face interaction. Several participants noted that the usefulness of in-person lectures—was a function of the presenter.

Overall, the exploratory evaluation indicated that the modules were a welcome supplement to the course and were effective in reinforcing key concepts. Participants retained knowledge for several weeks, although since subjects were self-selected, they may have been self-motivated to pay attention and master the online module materials.

"I am constantly searching for new ways to educate our program’s diverse audiences and reinforce watershed science concepts, " says Candice Rupprecht, state coordinator for the Master Watershed Steward program. "I am excited to know that online learning modules can enhance our program by offering additional independent learning opportunities for our volunteers.

Which of the following is true of the online learning（）

A. It can show the diligence of one particular learner in content knowledge learning

B. Many visitors of the site are impressed by its friendly interface

C. It can help program participants to carry out researches

D. It can enrich program participants’ experience in water conservation

下列哪一项不属于调查（　　）

A．人口普查

B．森林资源调查

C．水资源抽样调查

D．仔细观察牛

人的实践活动与动物本能活动的根本区别是( )。

A．活动性
B．目的性
C．实践性
D．预期性

一个女孩在一望无际的沼泽里迷路了，聪明的女孩没有慌乱，而是沿着自己一路留下的脚印回到出发的地方，开始试走新的路线，最终，她离开了茫茫无际的大沼泽。犯下错误后，只要能从中找到失误和欠缺之处，并及时改正，总能看清成功之路。由此可见（）

①谬误可以从反面不断推动真理的发展

②个人犯的错误与获得的真理成正比

③找出所犯错误的原因意味着接近真理

④真理和谬误可以相互转化没有严格界限

A.①③

B.③④

C.②③

D.①④

严重的精索静脉曲张最有效的治疗方法是

A．穿弹力裤
B．高位结扎，切断精索内静脉
C．阴囊托带
D．阴囊热敷
E．药物治疗