[ Exercise 4 ]

1. A number of innovative developments ( has , have ) been made in the Multi-component injection molding process in recent years.
2. A gas channel design that ( guides , guide ) the gas flow to the desired locations ( is , are ) one of the key factors that determine a successful application.
3. The delay time along with gas injection points ( is , are ) important in producing injection-molded parts of quality.
4. Neither the processing parameters nor the amount of polymer melt injection solely ( determine , determines ) a successful gas channel design.
5. To select the number and locations of gas injection points and to determine the amount of polymer melt injection ( is , are ) essential to a successful application.
6. Ergonomics ( aim , aims ) to integrate worker comfort and productivity.
7. Each of the factors ( contribute , contributes ) to a successful design.
8. The simulation in which the polymer melt flow ( occurs , occur ) in thin cavities ( provides , provide ) accurate predictions.
9. Establishing a general model or empirical formula in addition to describing the thickness variation of the skin melt that exists between the gas/melt interface and the cavity wall ( appear , appears ) to be necessary for further development.
10. The number of gas injection points ( are , is ) important in producing quality injection-molded parts.
11. The majority of factors heavily ( influences , influence ) product performance.
12. Accurately determining the interface shape of a bubble nose and properly selecting the film thickness ( is , are ) of primary concern.