Sentence:
"To trap a Fox, first a hole is dug at a forty five degree angle, a shallow depression is scooped out in front of the hole then the trap is covered $\qquad$ with finely sifted dirt so that the fox walks over without knowing about the hole until it falls for trap."

Context clues:
- The trap is covered so that the fox does not notice the hole.
- The covering must be done very carefully and subtly.
- The words should describe how the dirt is laid over the trap so that it's not detectable to the fox.

Analysis of options:
- A. permanently - means forever or lasting indefinitely. Not appropriate here because the focus is on subtlety, not duration.
- B. imperceptibly - means in a way that is not perceptible or noticeable. Fits perfectly because the fox shouldn't notice the trap.
- C. sporadically - means irregularly or infrequently. Doesn't fit the careful covering described.
- D. precariously - means in an unstable or insecure way. This might describe the cover too loosely placed, which is risky, but not fitting to fool the fox.
- E. slightly - means to a small degree. Could fit if referring to the thinness or delicateness of the cover.
- F. unsteadily - means insecurely or without balance. Not ideal since the goal is for the cover to hide the hole reliably.

Best two answers:
- B. imperceptibly - to emphasize the cover should be unnoticeable.
- E. slightly - to indicate the dirt is lightly or thinly spread, aiding invisibility.

Final answers:
B. imperceptibly
E. slightly