1、No terrorist group claimed responsibility for the bombings by Tuesday.
截至周二還沒有恐怖組織宣稱要對 * 事件負責(zé)。

2、The bomb was planted by a terrorist group or by a group of terrorists.
* 是由一群 * 置放的。

3、The bomb was planted by a terrorist group or by a group of terrorists
* 是由一群 * 置放的。