Nhận biết (M1)

Since the Hubble Space Telescope was launched into space in 1990, astronauts have needed to complete regular missions to repair the telescope and keep it working smoothly. Researchers hope that robots will soon be able to make these repairs. Employing robots instead of humans to make repairs will be helpful, as __________ astronauts to maintain the telescope can be expensive.

Which choice completes the text with the most logical and precise word or phrase?

• A.

  straightening

• B.

  relying on

• C.

  reducing

• D.

  forgetting about