三、克漏字測驗【請依照段落上下文意，選出最適當的答案】         In a span of five years, autonomous driving has gone from “maybe possible” to “inevitable” to “   16   .” InDecember 2018, Waymo officially started its robot-car paid service in the suburbs of Phoenix, Arizona. Thedetails of the program—open only to a few hundred test riders, and with human safety operators remainingbehind the wheel—may be not that   17   but don’t erase its significance. In this 21st-century gold rush,Waymo’s onetime monopoly has soon evaporated. Other   18   startups are running small-scale butrevenue-generating shuttle services. Every major automaker is pursuing the driverless tech, eager to rebuild itselfas “   19   .” Ride-hailing companies like Uber are also rushing to   20   the costly human drivers, while techgiants like Apple and Intel are looking to carve off their slice of the pie and fill niches in this burgeoningecosystem.
【題組】16.
(A) simply impossible
(B) totally refundable
(C) barely profitable
(D) commercially available