The learning of Chinese words is an important step if the learners want to acquire Chinese language. But the point that the foreign students who study in Chinese language school need to pay attention is the distinguishing of similar Chinese words in meanings and appearances. 摸索 and 探索 are important for learners to tell apart. The former one is to look for something with exploratory style like 摸索教学经验. Another meaning is to fumble with the help of touch like 在黑暗中摸索到台灯的开关.

摸索emphasizes to try to find the regularity, method and experience on the conditions that the directions are unknown and the experience is not enough. However, 探索carries the meaning of seeking for answers through a variety of ways like 探索宇宙and科学探索. The meaning of 探索is a little deeper than that of 摸索. Therefore, the objects of 探索are usually the profound principle, the hidden secret and confusing questions. For instance, 探索宇宙的奥秘已经不再是人类的梦想.

To express the meaning that something is not clear, you can choose both 模糊and含糊 but you should notice the tiny differences. 模糊is to say things are not clear to recognize like 印象模糊and字迹模糊. It is more often used to indicate appearance, shape, image and memory are difficult to recall of recognize. It is also applied to say it is difficult to tell apart because of lacking in knowledge and understanding. But 含糊is to say the language expression and attitude are not clear. For instance, 他说的很含糊，我没听懂.

If you want to express you are unfamiliar with something, you may use陌生. But in some case, 生疏is also available. 陌生is often used to indicate you did not know the things before, mostly for place and person. you can say 他的名字听起来很陌生. Students in qualified Mandarin program might be taught that 生疏 can be applied to describe things you didn’t know and also the things you are not familiar. For example,多年不来往，我们的关系生疏了.