Depths in the routes (Malacca and Singapore Straits) vary between 20 m and about 23 m, but there are many areas of sand-waves and depths are liable to change. The statement infers that (1.0)
A.depths in Malacca and Singapore Straits are stable B.depths in Malacca and Singapore Straits are changeable C.depths in Malacca and Singapore Straits are invariable D.depths in Malacca and Singapore Straits are the same all the time正确答案B
