Translate into English while choosing variants with may(might) can(could) must while matching the items on the right to the items on the left.

Должно быть, он забыл принести ключи.	??? He could have found the keys. He must have remembered to bring the keys. You might help him to find the keys. He may(might) haven't forgotten the keys He may(might) have found the keys. He may(might) not have forgotten to bring the keys. He may(might) be looking for the keys. He must have forgotten to bring the keys. He may(might) have been looking for the keys for 10 minutes. Probably no one was able to find the key. No one might have helped him to find the keys.
Возможно, он не забыл принести ключи.	??? He could have found the keys. He must have remembered to bring the keys. You might help him to find the keys. He may(might) haven't forgotten the keys He may(might) have found the keys. He may(might) not have forgotten to bring the keys. He may(might) be looking for the keys. He must have forgotten to bring the keys. He may(might) have been looking for the keys for 10 minutes. Probably no one was able to find the key. No one might have helped him to find the keys.
Возможно, он сейчас ищет ключи.	??? He could have found the keys. He must have remembered to bring the keys. You might help him to find the keys. He may(might) haven't forgotten the keys He may(might) have found the keys. He may(might) not have forgotten to bring the keys. He may(might) be looking for the keys. He must have forgotten to bring the keys. He may(might) have been looking for the keys for 10 minutes. Probably no one was able to find the key. No one might have helped him to find the keys.
Вообще то, он мог бы найти ключи.	??? He could have found the keys. He must have remembered to bring the keys. You might help him to find the keys. He may(might) haven't forgotten the keys He may(might) have found the keys. He may(might) not have forgotten to bring the keys. He may(might) be looking for the keys. He must have forgotten to bring the keys. He may(might) have been looking for the keys for 10 minutes. Probably no one was able to find the key. No one might have helped him to find the keys.
Должно быть, он не забыл принести ключи	??? He could have found the keys. He must have remembered to bring the keys. You might help him to find the keys. He may(might) haven't forgotten the keys He may(might) have found the keys. He may(might) not have forgotten to bring the keys. He may(might) be looking for the keys. He must have forgotten to bring the keys. He may(might) have been looking for the keys for 10 minutes. Probably no one was able to find the key. No one might have helped him to find the keys.
Наверно, он ищет ключи уже 10 минут.	??? He could have found the keys. He must have remembered to bring the keys. You might help him to find the keys. He may(might) haven't forgotten the keys He may(might) have found the keys. He may(might) not have forgotten to bring the keys. He may(might) be looking for the keys. He must have forgotten to bring the keys. He may(might) have been looking for the keys for 10 minutes. Probably no one was able to find the key. No one might have helped him to find the keys.
Возможно, он уже нашел ключи.	??? He could have found the keys. He must have remembered to bring the keys. You might help him to find the keys. He may(might) haven't forgotten the keys He may(might) have found the keys. He may(might) not have forgotten to bring the keys. He may(might) be looking for the keys. He must have forgotten to bring the keys. He may(might) have been looking for the keys for 10 minutes. Probably no one was able to find the key. No one might have helped him to find the keys.
Ты мог бы помочь ему найти ключи. (сейчас)	??? He could have found the keys. He must have remembered to bring the keys. You might help him to find the keys. He may(might) haven't forgotten the keys He may(might) have found the keys. He may(might) not have forgotten to bring the keys. He may(might) be looking for the keys. He must have forgotten to bring the keys. He may(might) have been looking for the keys for 10 minutes. Probably no one was able to find the key. No one might have helped him to find the keys.
Наверно, никто не помог ему найти ключи.	??? He could have found the keys. He must have remembered to bring the keys. You might help him to find the keys. He may(might) haven't forgotten the keys He may(might) have found the keys. He may(might) not have forgotten to bring the keys. He may(might) be looking for the keys. He must have forgotten to bring the keys. He may(might) have been looking for the keys for 10 minutes. Probably no one was able to find the key. No one might have helped him to find the keys.
Должно быть, никто не помог ему найти ключи.	??? He could have found the keys. He must have remembered to bring the keys. You might help him to find the keys. He may(might) haven't forgotten the keys He may(might) have found the keys. He may(might) not have forgotten to bring the keys. He may(might) be looking for the keys. He must have forgotten to bring the keys. He may(might) have been looking for the keys for 10 minutes. Probably no one was able to find the key. No one might have helped him to find the keys.