1.  具体使用什么介词，与后面名词的意义搭配有关。举例说明：

The computer is in use now. 电脑正在使用中。

These high-tech products are on display these days. 近几天这些高科技产品正在展出中。

The highway is under construction. 这条公路正在建设中。

in use 的 in 表示“使用过程、使用期间”；on display 的 on 表示“在展览架上”；under construction 的under表示“受到控制或处于......之下”。

2.  以上介词短语“in/on/under + 名词”，确实含有被动意义。其特征是介词后的名词具有动作意义，都有相应的同源动词。相当于该动词现在进行时的被动语态。

The computer is being used now.

These high-tech products are being displayed these days.

The highway is being constructed.

介词under+抽象名词和介词in+抽象名词区别如下

【1】under 表示“某事/某物在经历某事的过程中”有“被动含义”相当于进行体被动结构。

The hotel is still under construction.旅馆还在兴建中。=The hotel is still being constructed.

The matter is under investigation.此事正在调查中。=The matter is being investigated.

【2】in 表示“某物在被使用的过程中”有“被动含义” 相当与进行体被动结构。

The line is in use.  电话占线.=The line is being used.

These old machines are still in use.  这些陈旧的机器仍在使用.=These old machines are still being used.