| Science | etw erforschen + | to research sth + | General | B |
Most Common Compounds Set 1:
Most Common Compounds Set 2 :
| Intermediate -Advanced: 2517 (noun: secret, profound mystery)  Scientists are constantly exploring the mysteries of the universe.  Wissenschaftler erforschen ständig die Geheimnisse des Universums.  Các nhà khoa học không ngừng khám phá những bí ẩn của vũ trụ. |