These three characters look alike and are high frequency, they are good characters for judgement.

真 zhen1

is originally an image of two people at a food pot: the food is represented by the cross on top and it is GENUINE. The two people transformed into two hands beneath the food pot is the square in the middle. They are inspecting the food to make sure it is GENUINE
Zealous
Heartfelt
Expressive
Newbies REAL

其 qi2

this is a high frequency example of a rare method for forming characters: 假借 iǎ jiè or “borrowed” “phonetic loan” characters. It’s an image of a woven dustpan, but that character was “borrowed” to represent the same sound in the more general context of IT HIS HERS THEIR SUCH THAT
Basket on top, 2 graspy hands below.

Query
Intellectuals IT

Question
IT.

具ju4

is the image of two hands (the dots below) handling a pot of food on top (the square with lines). See hanziyuan thereto.
TOOL

Justice
Usually  MASK, TOOL, FURNITURE

家具 jia1ju4 furniture
面具 mian4ju4 mask
具 ju4 tool

So here is a sample sentence using all three:

我不是魔鬼，我是真的。 其他的人穿面具，我没有。

真 real
生活的其他的人 the lives of others
面具 masks