《后汉书·列传·刘赵淳于江刘周赵列传》
只挖个沟坎，能放下棺木郭即可，棺木回了即葬，平地不要筑坟堆，不必选期择日，也不必祭奠，不必在墓侧守丧，不要在坟头种树。
但欲制坎，令容棺椁，棺归即葬，平地无坟。勿卜时日，葬无设奠，勿留墓侧，无起封树。
Just dig a ditch that can accommodate the coffin. Bury the coffin immediately after it is closed. Do not build a tomb on the flat ground or choose an auspicious day. Do not offer sacrifices, guard the tomb, or plant trees on the tomb.
<s>[INST] Identify the key themes in this Classical Chinese text and explain them in English: 但欲制坎，令容棺椁，棺归即葬，平地无坟。勿卜时日，葬无设奠，勿留墓侧，无起封树。 [/INST] Just dig a ditch that can accommodate the coffin. Bury the coffin immediately after it is closed. Do not build a tomb on the flat ground or choose an auspicious day. Do not offer sacrifices, guard the tomb, or plant trees on the tomb.</s>
Identify the key themes in this Classical Chinese text and explain them in English: 但欲制坎，令容棺椁，棺归即葬，平地无坟。勿卜时日，葬无设奠，勿留墓侧，无起封树。
user
Just dig a ditch that can accommodate the coffin. Bury the coffin immediately after it is closed. Do not build a tomb on the flat ground or choose an auspicious day. Do not offer sacrifices, guard the tomb, or plant trees on the tomb.
assistant